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2023-04-28runtime: resolve checkdead panic by refining `startm` lock handling in ↵Lucien Coffe
caller context This change addresses a `checkdead` panic caused by a race condition between `sysmon->startm` and `checkdead` callers, due to prematurely releasing the scheduler lock. The solution involves allowing a `startm` caller to acquire the scheduler lock and call `startm` in this context. A new `lockheld` bool argument is added to `startm`, which manages all lock and unlock calls within the function. The`startIdle` function variable in `injectglist` is updated to call `startm` with the lock held, ensuring proper lock handling in this specific case. This refined lock handling resolves the observed race condition issue. Fixes #59600 Change-Id: I11663a15536c10c773fc2fde291d959099aa71be Reviewed-on: https://go-review.googlesource.com/c/go/+/487316 Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Michael Pratt <mpratt@google.com>
2023-04-26runtime/cgo: store M for C-created thread in pthread keyMichael Pratt
This reapplies CL 481061, with the followup fixes in CL 482975, CL 485315, and CL 485316 incorporated. CL 481061, by doujiang24 <doujiang24@gmail.com>, speed up C to Go calls by binding the M to the C thread. See below for its description. CL 482975 is a followup fix to a C declaration in testprogcgo. CL 485315 is a followup fix for x_cgo_getstackbound on Illumos. CL 485316 is a followup cleanup for ppc64 assembly. [Original CL 481061 description] This reapplies CL 392854, with the followup fixes in CL 479255, CL 479915, and CL 481057 incorporated. CL 392854, by doujiang24 <doujiang24@gmail.com>, speed up C to Go calls by binding the M to the C thread. See below for its description. CL 479255 is a followup fix for a small bug in ARM assembly code. CL 479915 is another followup fix to address C to Go calls after the C code uses some stack, but that CL is also buggy. CL 481057, by Michael Knyszek, is a followup fix for a memory leak bug of CL 479915. [Original CL 392854 description] In a C thread, it's necessary to acquire an extra M by using needm while invoking a Go function from C. But, needm and dropm are heavy costs due to the signal-related syscalls. So, we change to not dropm while returning back to C, which means binding the extra M to the C thread until it exits, to avoid needm and dropm on each C to Go call. Instead, we only dropm while the C thread exits, so the extra M won't leak. When invoking a Go function from C: Allocate a pthread variable using pthread_key_create, only once per shared object, and register a thread-exit-time destructor. And store the g0 of the current m into the thread-specified value of the pthread key, only once per C thread, so that the destructor will put the extra M back onto the extra M list while the C thread exits. When returning back to C: Skip dropm in cgocallback, when the pthread variable has been created, so that the extra M will be reused the next time invoke a Go function from C. This is purely a performance optimization. The old version, in which needm & dropm happen on each cgo call, is still correct too, and we have to keep the old version on systems with cgo but without pthreads, like Windows. This optimization is significant, and the specific value depends on the OS system and CPU, but in general, it can be considered as 10x faster, for a simple Go function call from a C thread. For the newly added BenchmarkCGoInCThread, some benchmark results: 1. it's 28x faster, from 3395 ns/op to 121 ns/op, in darwin OS & Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz 2. it's 6.5x faster, from 1495 ns/op to 230 ns/op, in Linux OS & Intel(R) Xeon(R) CPU E5-2630 0 @ 2.30GHz [CL 479915 description] Currently, when C calls into Go the first time, we grab an M using needm, which sets m.g0's stack bounds using the SP. We don't know how big the stack is, so we simply assume 32K. Previously, when the Go function returns to C, we drop the M, and the next time C calls into Go, we put a new stack bound on the g0 based on the current SP. After CL 392854, we don't drop the M, and the next time C calls into Go, we reuse the same g0, without recomputing the stack bounds. If the C code uses quite a bit of stack space before calling into Go, the SP may be well below the 32K stack bound we assumed, so the runtime thinks the g0 stack overflows. This CL makes needm get a more accurate stack bound from pthread. (In some platforms this may still be a guess as we don't know exactly where we are in the C stack), but it is probably better than simply assuming 32K. [CL 485500 description] CL 479915 passed the G to _cgo_getstackbound for direct updates to gp.stack.lo. A G can be reused on a new thread after the previous thread exited. This could trigger the C TSAN race detector because it couldn't see the synchronization in Go (lockextra) preventing the same G from being used on multiple threads at the same time. We work around this by passing the address of a stack variable to _cgo_getstackbound rather than the G. The stack is generally unique per thread, so TSAN won't see the same address from multiple threads. Even if stacks are reused across threads by pthread, C TSAN should see the synchonization in the stack allocator. A regression test is added to misc/cgo/testsanitizer. Fixes #51676. Fixes #59294. Fixes #59678. Change-Id: Ic62be31a06ee83568215e875a891df37084e08ca Reviewed-on: https://go-review.googlesource.com/c/go/+/485500 TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com> Run-TryBot: Michael Pratt <mpratt@google.com>
2023-04-24runtime: add raceFiniLock to lock rankingIan Lance Taylor
Also preserve the PC/SP in reentersyscall when doing lock ranking. The test is TestDestructorCallbackRace with the staticlockranking experiment enabled. For #59711 Change-Id: I87ac1d121ec0d399de369666834891ab9e7d11b0 Reviewed-on: https://go-review.googlesource.com/c/go/+/487955 Run-TryBot: Ian Lance Taylor <iant@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com> Auto-Submit: Ian Lance Taylor <iant@google.com> Run-TryBot: Ian Lance Taylor <iant@google.com>
2023-04-21runtime: prevent double lock in checkdead by unlocking before throwsLucien Coffe
This change resolves an issue where checkdead could result in a double lock when shedtrace is enabled. This fix involves adding unlocks before all throws in the checkdead function to ensure the scheduler lock is properly released. Fixes #59758 Change-Id: If3ddf9969f4582c3c88dee9b9ecc355a63958103 Reviewed-on: https://go-review.googlesource.com/c/go/+/487375 Run-TryBot: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com> Auto-Submit: Michael Pratt <mpratt@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2023-04-21runtime: tidy _Stack* constant namingAustin Clements
For #59670. Change-Id: I0efa743edc08e48dc8d906803ba45e9f641369db Reviewed-on: https://go-review.googlesource.com/c/go/+/486977 Reviewed-by: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Auto-Submit: Austin Clements <austin@google.com> Run-TryBot: Austin Clements <austin@google.com>
2023-04-21internal/abi, runtime, cmd: merge funcFlag_* consts into internal/abiAustin Clements
For #59670. Change-Id: Ie784ba4dd2701e4f455e1abde4a6bfebee4b1387 Reviewed-on: https://go-review.googlesource.com/c/go/+/485496 Reviewed-by: David Chase <drchase@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Austin Clements <austin@google.com> Auto-Submit: Austin Clements <austin@google.com>
2023-04-20Revert "runtime: tidy _Stack* constant naming"Austin Clements
This reverts commit CL 486381. Submitted out of order and breaks bootstrap. Change-Id: Ia472111cb966e884a48f8ee3893b3bf4b4f4f875 Reviewed-on: https://go-review.googlesource.com/c/go/+/486915 Reviewed-by: David Chase <drchase@google.com> TryBot-Bypass: Austin Clements <austin@google.com>
2023-04-20runtime: tidy _Stack* constant namingAustin Clements
For #59670. Change-Id: I4476d6f92663e8a825d063d6e6a7fc9a2ac99d4d Reviewed-on: https://go-review.googlesource.com/c/go/+/486381 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>
2023-04-17Revert "runtime/cgo: store M for C-created thread in pthread key"Michael Pratt
This reverts CL 481061. Reason for revert: When built with C TSAN, x_cgo_getstackbound triggers race detection on `g->stacklo` because the synchronization is in Go, which isn't instrumented. For #51676. For #59294. For #59678. Change-Id: I38afcda9fcffd6537582a39a5214bc23dc147d47 Reviewed-on: https://go-review.googlesource.com/c/go/+/485275 TryBot-Result: Gopher Robot <gobot@golang.org> Auto-Submit: Michael Pratt <mpratt@google.com> Run-TryBot: Michael Pratt <mpratt@google.com> Reviewed-by: Than McIntosh <thanm@google.com>
2023-04-14cmd/link: establish dependable package initialization orderKeith Randall
(This is a retry of CL 462035 which was reverted at 474976. The only change from that CL is the aix fix SRODATA->SNOPTRDATA at inittask.go:141) As described here: https://github.com/golang/go/issues/31636#issuecomment-493271830 "Find the lexically earliest package that is not initialized yet, but has had all its dependencies initialized, initialize that package, and repeat." Simplify the runtime a bit, by just computing the ordering required in the linker and giving a list to the runtime. Update #31636 Fixes #57411 RELNOTE=yes Change-Id: I28c09451d6aa677d7394c179d23c2c02c503fc56 Reviewed-on: https://go-review.googlesource.com/c/go/+/478916 Reviewed-by: Than McIntosh <thanm@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org>
2023-04-03runtime/cgo: store M for C-created thread in pthread keydoujiang24
This reapplies CL 392854, with the followup fixes in CL 479255, CL 479915, and CL 481057 incorporated. CL 392854, by doujiang24 <doujiang24@gmail.com>, speed up C to Go calls by binding the M to the C thread. See below for its description. CL 479255 is a followup fix for a small bug in ARM assembly code. CL 479915 is another followup fix to address C to Go calls after the C code uses some stack, but that CL is also buggy. CL 481057, by Michael Knyszek, is a followup fix for a memory leak bug of CL 479915. [Original CL 392854 description] In a C thread, it's necessary to acquire an extra M by using needm while invoking a Go function from C. But, needm and dropm are heavy costs due to the signal-related syscalls. So, we change to not dropm while returning back to C, which means binding the extra M to the C thread until it exits, to avoid needm and dropm on each C to Go call. Instead, we only dropm while the C thread exits, so the extra M won't leak. When invoking a Go function from C: Allocate a pthread variable using pthread_key_create, only once per shared object, and register a thread-exit-time destructor. And store the g0 of the current m into the thread-specified value of the pthread key, only once per C thread, so that the destructor will put the extra M back onto the extra M list while the C thread exits. When returning back to C: Skip dropm in cgocallback, when the pthread variable has been created, so that the extra M will be reused the next time invoke a Go function from C. This is purely a performance optimization. The old version, in which needm & dropm happen on each cgo call, is still correct too, and we have to keep the old version on systems with cgo but without pthreads, like Windows. This optimization is significant, and the specific value depends on the OS system and CPU, but in general, it can be considered as 10x faster, for a simple Go function call from a C thread. For the newly added BenchmarkCGoInCThread, some benchmark results: 1. it's 28x faster, from 3395 ns/op to 121 ns/op, in darwin OS & Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz 2. it's 6.5x faster, from 1495 ns/op to 230 ns/op, in Linux OS & Intel(R) Xeon(R) CPU E5-2630 0 @ 2.30GHz [CL 479915 description] Currently, when C calls into Go the first time, we grab an M using needm, which sets m.g0's stack bounds using the SP. We don't know how big the stack is, so we simply assume 32K. Previously, when the Go function returns to C, we drop the M, and the next time C calls into Go, we put a new stack bound on the g0 based on the current SP. After CL 392854, we don't drop the M, and the next time C calls into Go, we reuse the same g0, without recomputing the stack bounds. If the C code uses quite a bit of stack space before calling into Go, the SP may be well below the 32K stack bound we assumed, so the runtime thinks the g0 stack overflows. This CL makes needm get a more accurate stack bound from pthread. (In some platforms this may still be a guess as we don't know exactly where we are in the C stack), but it is probably better than simply assuming 32K. Fixes #51676. Fixes #59294. Change-Id: I9bf1400106d5c08ce621d2ed1df3a2d9e3f55494 Reviewed-on: https://go-review.googlesource.com/c/go/+/481061 Reviewed-by: Michael Knyszek <mknyszek@google.com> Run-TryBot: Cherry Mui <cherryyz@google.com> Reviewed-by: DeJiang Zhu (doujiang) <doujiang24@gmail.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2023-03-31Revert "runtime/cgo: store M for C-created thread in pthread key"Cherry Mui
This reverts CL 392854. Reason for revert: caused #59294, which was derived from google internal tests. The attempted fix of #59294 caused more breakage. Change-Id: I5a061561ac2740856b7ecc09725ac28bd30f8bba Reviewed-on: https://go-review.googlesource.com/c/go/+/481060 Reviewed-by: Heschi Kreinick <heschi@google.com> Run-TryBot: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2023-03-31Revert "runtime: get a better g0 stack bound in needm"Cherry Mui
This reverts CL 479915. Reason for revert: breaks a lot google internal tests. Change-Id: I13a9422e810af7ba58cbf4a7e6e55f4d8cc0ca51 Reviewed-on: https://go-review.googlesource.com/c/go/+/481055 Reviewed-by: Chressie Himpel <chressie@google.com> Run-TryBot: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2023-03-30runtime: get a better g0 stack bound in needmCherry Mui
Currently, when C calls into Go the first time, we grab an M using needm, which sets m.g0's stack bounds using the SP. We don't know how big the stack is, so we simply assume 32K. Previously, when the Go function returns to C, we drop the M, and the next time C calls into Go, we put a new stack bound on the g0 based on the current SP. After CL 392854, we don't drop the M, and the next time C calls into Go, we reuse the same g0, without recomputing the stack bounds. If the C code uses quite a bit of stack space before calling into Go, the SP may be well below the 32K stack bound we assumed, so the runtime thinks the g0 stack overflows. This CL makes needm get a more accurate stack bound from pthread. (In some platforms this may still be a guess as we don't know exactly where we are in the C stack), but it is probably better than simply assuming 32K. For #59294. Change-Id: Ie52a8f931e0648d8753e4c1dbe45468b8748b527 Reviewed-on: https://go-review.googlesource.com/c/go/+/479915 Run-TryBot: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2023-03-30runtime/trace: use regular unwinding for cgo callbacksFelix Geisendörfer
Introduce a new m.incgocallback field that is true while C code calls into Go code. Use it in the tracer in order to fallback to the default unwinder instead of frame pointer unwinding for this scenario. The existing fields (incgo, ncgo) were not sufficient to detect the case where a thread created in C calls into Go code. Motivation: 1. Take advantage of a cgo symbolizer, if registered, to unwind through C stacks without frame pointers. 2. Reduce the chance of crashes. It seems unsafe to follow frame pointers when there could be C code that was compiled without frame pointers. Removing the curgp.m.incgocallback check in traceStackID shows the following minor differences between frame pointer unwinding and the default unwinder when there is no cgo symbolizer involved. trace_test.go:60: "goCalledFromCThread": got stack: main.goCalledFromCThread /src/runtime/testdata/testprogcgo/trace.go:58 _cgoexp_45c15a3efb3a_goCalledFromCThread _cgo_gotypes.go:694 runtime.cgocallbackg1 /src/runtime/cgocall.go:318 runtime.cgocallbackg /src/runtime/cgocall.go:236 runtime.cgocallback /src/runtime/asm_amd64.s:998 crosscall2 /src/runtime/cgo/asm_amd64.s:30 want stack: main.goCalledFromCThread /src/runtime/testdata/testprogcgo/trace.go:58 _cgoexp_45c15a3efb3a_goCalledFromCThread _cgo_gotypes.go:694 runtime.cgocallbackg1 /src/runtime/cgocall.go:318 runtime.cgocallbackg /src/runtime/cgocall.go:236 runtime.cgocallback /src/runtime/asm_amd64.s:998 trace_test.go:60: "goCalledFromC": got stack: main.goCalledFromC /src/runtime/testdata/testprogcgo/trace.go:51 _cgoexp_45c15a3efb3a_goCalledFromC _cgo_gotypes.go:687 runtime.cgocallbackg1 /src/runtime/cgocall.go:318 runtime.cgocallbackg /src/runtime/cgocall.go:236 runtime.cgocallback /src/runtime/asm_amd64.s:998 crosscall2 /src/runtime/cgo/asm_amd64.s:30 runtime.asmcgocall /src/runtime/asm_amd64.s:848 main._Cfunc_cCalledFromGo _cgo_gotypes.go:263 main.goCalledFromGo /src/runtime/testdata/testprogcgo/trace.go:46 main.Trace /src/runtime/testdata/testprogcgo/trace.go:37 main.main /src/runtime/testdata/testprogcgo/main.go:34 want stack: main.goCalledFromC /src/runtime/testdata/testprogcgo/trace.go:51 _cgoexp_45c15a3efb3a_goCalledFromC _cgo_gotypes.go:687 runtime.cgocallbackg1 /src/runtime/cgocall.go:318 runtime.cgocallbackg /src/runtime/cgocall.go:236 runtime.cgocallback /src/runtime/asm_amd64.s:998 runtime.systemstack_switch /src/runtime/asm_amd64.s:463 runtime.cgocall /src/runtime/cgocall.go:168 main._Cfunc_cCalledFromGo _cgo_gotypes.go:263 main.goCalledFromGo /src/runtime/testdata/testprogcgo/trace.go:46 main.Trace /src/runtime/testdata/testprogcgo/trace.go:37 main.main /src/runtime/testdata/testprogcgo/main.go:34 For #16638 Change-Id: I95fa27a3170c5abd923afc6eadab4eae777ced31 Reviewed-on: https://go-review.googlesource.com/c/go/+/474916 TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Run-TryBot: Felix Geisendörfer <felix.geisendoerfer@datadoghq.com>
2023-03-24runtime/cgo: store M for C-created thread in pthread keydoujiang24
In a C thread, it's necessary to acquire an extra M by using needm while invoking a Go function from C. But, needm and dropm are heavy costs due to the signal-related syscalls. So, we change to not dropm while returning back to C, which means binding the extra M to the C thread until it exits, to avoid needm and dropm on each C to Go call. Instead, we only dropm while the C thread exits, so the extra M won't leak. When invoking a Go function from C: Allocate a pthread variable using pthread_key_create, only once per shared object, and register a thread-exit-time destructor. And store the g0 of the current m into the thread-specified value of the pthread key, only once per C thread, so that the destructor will put the extra M back onto the extra M list while the C thread exits. When returning back to C: Skip dropm in cgocallback, when the pthread variable has been created, so that the extra M will be reused the next time invoke a Go function from C. This is purely a performance optimization. The old version, in which needm & dropm happen on each cgo call, is still correct too, and we have to keep the old version on systems with cgo but without pthreads, like Windows. This optimization is significant, and the specific value depends on the OS system and CPU, but in general, it can be considered as 10x faster, for a simple Go function call from a C thread. For the newly added BenchmarkCGoInCThread, some benchmark results: 1. it's 28x faster, from 3395 ns/op to 121 ns/op, in darwin OS & Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz 2. it's 6.5x faster, from 1495 ns/op to 230 ns/op, in Linux OS & Intel(R) Xeon(R) CPU E5-2630 0 @ 2.30GHz Fixes #51676 Change-Id: I380702fe2f9b6b401b2d6f04b0aba990f4b9ee6c GitHub-Last-Rev: 93dc64ad98e5583372e41f65ee4b7ab78b5aff51 GitHub-Pull-Request: golang/go#51679 Reviewed-on: https://go-review.googlesource.com/c/go/+/392854 Reviewed-by: Ian Lance Taylor <iant@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: thepudds <thepudds1460@gmail.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
2023-03-21runtime: for deep stacks, print both the top 50 and bottom 50 framesAustin Clements
This is relatively easy using the new traceback iterator. Ancestor tracebacks are now limited to 50 frames. We could keep that at 100, but the fact that it used 100 before seemed arbitrary and unnecessary. Fixes #7181 Updates #54466 Change-Id: If693045881d84848f17e568df275a5105b6f1cb0 Reviewed-on: https://go-review.googlesource.com/c/go/+/475960 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com>
2023-03-10runtime: new API for filling PC traceback buffersAustin Clements
Currently, filling PC traceback buffers is one of the jobs of gentraceback. This moves it into a new function, tracebackPCs, with a simple API built around unwinder, and changes all callers to use this new API. Updates #54466. Change-Id: Id2038bded81bf533a5a4e71178a7c014904d938c Reviewed-on: https://go-review.googlesource.com/c/go/+/468300 Reviewed-by: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Austin Clements <austin@google.com>
2023-03-09Revert "cmd/link: establish dependable package initialization order"Keith Randall
This reverts commit ce2a609909d9de3391a99a00fe140506f724f933. aka CL 462035 Reason for revert: this CL is causing some problems in some internal Google programs. Change-Id: I4476b8d8d2c3d7b5703d1d85c93baebb4b4e5d26 Reviewed-on: https://go-review.googlesource.com/c/go/+/474976 Reviewed-by: Cherry Mui <cherryyz@google.com> Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com>
2023-03-03cmd/link: establish dependable package initialization orderKeith Randall
As described here: https://github.com/golang/go/issues/31636#issuecomment-493271830 "Find the lexically earliest package that is not initialized yet, but has had all its dependencies initialized, initialize that package, and repeat." Simplify the runtime a bit, by just computing the ordering required in the linker and giving a list to the runtime. Update #31636 Fixes #57411 RELNOTE=yes Change-Id: I1e4d3878ebe6e8953527aedb730824971d722cac Reviewed-on: https://go-review.googlesource.com/c/go/+/462035 Reviewed-by: Than McIntosh <thanm@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org>
2023-03-02all: move //go: function directives directly above functionsMichael Pratt
These directives affect the next declaration, so the existing form is valid, but can be confusing because it is easy to miss. Move then directly above the declaration for improved readability. CL 69120 previously moved the Gosched nosplit away to hide it from documentation. Since CL 224737, directives are automatically excluded from documentation. Change-Id: I8ebf2d47fbb5e77c6f40ed8afdf79eaa4f4e335e Reviewed-on: https://go-review.googlesource.com/c/go/+/472957 Run-TryBot: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
2023-02-21runtime: record parent goroutine ID, and print it in stack tracesNick Ripley
Fixes #38651 Change-Id: Id46d684ee80e208c018791a06c26f304670ed159 Reviewed-on: https://go-review.googlesource.com/c/go/+/435337 Run-TryBot: Nick Ripley <nick.ripley@datadoghq.com> Reviewed-by: Ethan Reesor <ethan.reesor@gmail.com> Auto-Submit: Michael Pratt <mpratt@google.com> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2023-02-16runtime: reimplement GODEBUG=cgocheck=2 as a GOEXPERIMENTKeith Randall
Move this knob from a binary-startup thing to a build-time thing. This will enable followon optmizations to the write barrier. Change-Id: Ic3323348621c76a7dc390c09ff55016b19c43018 Reviewed-on: https://go-review.googlesource.com/c/go/+/447778 Reviewed-by: Michael Knyszek <mknyszek@google.com> Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>
2023-02-08runtime: correct typosOleksandr Redko
- Fix typo in throw error message for arena. - Correct typos in assembly and Go comments. - Fix log message in TestTraceCPUProfile. Change-Id: I874c9e8cd46394448b6717bc6021aa3ecf319d16 GitHub-Last-Rev: d27fad4d3cea81cc7a4ca6917985bcf5fa49b0e0 GitHub-Pull-Request: golang/go#58375 Reviewed-on: https://go-review.googlesource.com/c/go/+/465975 Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Run-TryBot: Ian Lance Taylor <iant@google.com> Auto-Submit: Ian Lance Taylor <iant@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-12-05runtime: prioritize VDSO and libcall unwinding in profilerCherry Mui
In the profiler, when unwinding the stack, we have special handling for VDSO calls. Currently, the special handling is only used when the normal unwinding fails. If the signal lands in the function that makes the VDSO call (e.g. nanotime1) and after the stack switch, the normal unwinding doesn't fail but gets a stack trace with exactly one frame (the nanotime1 frame). The stack trace stops because of the stack switch. This 1-frame stack trace is not as helpful. Instead, if vdsoSP is set, we know we are in VDSO call or right before or after it, so use vdsoPC and vdsoSP for unwinding. Do the same for libcall. Also remove _TraceTrap for VDSO unwinding, as vdsoPC and vdsoSP correspond to a call, not an interrupted instruction. Fixes #56574. Change-Id: I799aa7644d0c1e2715ab038a9eef49481dd3a7f5 Reviewed-on: https://go-review.googlesource.com/c/go/+/455166 Run-TryBot: Cherry Mui <cherryyz@google.com> Reviewed-by: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-11-18all: add missing periods in commentscui fliter
Change-Id: I69065f8adf101fdb28682c55997f503013a50e29 Reviewed-on: https://go-review.googlesource.com/c/go/+/449757 Auto-Submit: Ian Lance Taylor <iant@google.com> Reviewed-by: Joedian Reid <joedian@golang.org> Reviewed-by: Keith Randall <khr@google.com> Reviewed-by: Keith Randall <khr@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Joedian Reid <joedian@golang.org> Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com>
2022-11-18runtime: add page tracerMichael Knyszek
This change adds a new GODEBUG flag called pagetrace that writes a low-overhead trace of how pages of memory are managed by the Go runtime. The page tracer is kept behind a GOEXPERIMENT flag due to a potential security risk for setuid binaries. Change-Id: I6f4a2447d02693c25214400846a5d2832ad6e5c0 Reviewed-on: https://go-review.googlesource.com/c/go/+/444157 Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: David Chase <drchase@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-11-10runtime: consolidate some low-level error reportingIan Lance Taylor
Use a single writeErrStr function. Avoid using global variables. Use a single version of some error messages rather than duplicating the messages in OS-specific files. Change-Id: If259fbe78faf797f0a21337d14472160ca03efa0 Reviewed-on: https://go-review.googlesource.com/c/go/+/447055 Run-TryBot: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com> Auto-Submit: Ian Lance Taylor <iant@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2022-11-07runtime: yield in goschedIfBusy if gp.preemptMichael Pratt
runtime.bgsweep contains an infinite loop. With aggressive enough inlining, it may not perform any CALLs on a typical iteration. If the runtime trying to preempt this goroutine, the lack of CALLs may prevent preemption for ever occurring. bgsweep does happen to call goschedIfBusy. Add a preempt check there to make sure we yield eventually. For #55022. Change-Id: If22eb86fd6a626094b3c56dc745c8e4243b0fb40 Reviewed-on: https://go-review.googlesource.com/c/go/+/447135 Run-TryBot: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
2022-10-18runtime: always keep global reference to mp until mexit completesMichael Pratt
Ms are allocated via standard heap allocation (`new(m)`), which means we must keep them alive (i.e., reachable by the GC) until we are completely done using them. Ms are primarily reachable through runtime.allm. However, runtime.mexit drops the M from allm fairly early, long before it is done using the M structure. If that was the last reference to the M, it is now at risk of being freed by the GC and used for some other allocation, leading to memory corruption. Ms with a Go-allocated stack coincidentally already keep a reference to the M in sched.freem, so that the stack can be freed lazily. This reference has the side effect of keeping this Ms reachable. However, Ms with an OS stack skip this and are at risk of corruption. Fix this lifetime by extending sched.freem use to all Ms, with the value of mp.freeWait determining whether the stack needs to be freed or not. Fixes #56243. Change-Id: Ic0c01684775f5646970df507111c9abaac0ba52e Reviewed-on: https://go-review.googlesource.com/c/go/+/443716 TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Michael Pratt <mpratt@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2022-10-05runtime: avoid initializing MemProfileRate in init functionWang Deyu
Fixes #55100 Change-Id: Ibbff921e74c3a416fd8bb019d20410273961c015 Reviewed-on: https://go-review.googlesource.com/c/go/+/431315 Auto-Submit: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Michael Pratt <mpratt@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2022-09-27runtime/trace: add missing events for the locked g in extra M.doujiang24
Extra Ms may lead to the "no consistent ordering of events possible" error when parsing trace file with cgo enabled, since: 1. The gs in the extra Ms may be in `_Gdead` status while starting trace by invoking `runtime.StartTrace`, 2. and these gs will trigger `traceEvGoSysExit` events in `runtime.exitsyscall` when invoking go functions from c, 3. then, the events of those gs are under non-consistent ordering, due to missing the previous events. Add two events, `traceEvGoCreate` and `traceEvGoInSyscall`, in `runtime.StartTrace`, will make the trace parser happy. Fixes #29707 Change-Id: I2fd9d1713cda22f0ddb36efe1ab351f88da10881 GitHub-Last-Rev: 7bbfddb81b70041250e3c59ce53bea44f7afd2c3 GitHub-Pull-Request: golang/go#54974 Reviewed-on: https://go-review.googlesource.com/c/go/+/429858 Run-TryBot: Michael Pratt <mpratt@google.com> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Bryan Mills <bcmills@google.com> Run-TryBot: xie cui <523516579@qq.com> TryBot-Result: Gopher Robot <gobot@golang.org> Auto-Submit: Michael Pratt <mpratt@google.com>
2022-09-26runtime: add an exit hook facilityThan McIntosh
Add a new API (not public/exported) for registering a function with the runtime that should be called when program execution terminates, to be used in the new code coverage re-implementation. The API looks like func addExitHook(f func(), runOnNonZeroExit bool) The first argument is the function to be run, second argument controls whether the function is invoked even if there is a call to os.Exit with a non-zero status. Exit hooks are run in reverse order of registration, e.g. the first hook to be registered will be the last to run. Exit hook functions are not allowed to panic or to make calls to os.Exit. Updates #51430. Change-Id: I906f8c5184b7c1666f05a62cfc7833bf1a4300c4 Reviewed-on: https://go-review.googlesource.com/c/go/+/354790 TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Than McIntosh <thanm@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2022-09-16runtime: tweak bgsweep "low-priority" heuristicMichael Anthony Knyszek
Currently bgsweep attempts to be a low-priority background goroutine that runs mainly when the application is mostly idle. To avoid complicating the scheduler further, it achieves this with a simple heuristic: call Gosched after each span swept. While this is somewhat inefficient as there's scheduling overhead on each iteration, it's mostly fine because it tends to just come out of idle time anyway. In a busy system, the call to Gosched quickly puts bgsweep at the back of scheduler queues. However, what's problematic about this heuristic is the number of tracing events it produces. Average span sweeping latencies have been measured as low as 30 ns, so every 30 ns in the sweep phase, with available idle time, there would be a few trace events emitted. This could result in an overwhelming number, making traces much larger than they need to be. It also pollutes other observability tools, like the scheduling latencies runtime metric, because bgsweep stays runnable the whole time. This change fixes these problems with two modifications to the heursitic: 1. Check if there are any idle Ps before yielding. If there are, don't yield. 2. Sweep at least 10 spans before trying to yield. (1) is doing most of the work here. This change assumes that the presence of idle Ps means that there is available CPU time, so bgsweep is already making use of idle time and there's no reason it should stop. This will have the biggest impact on the aforementioned issues. (2) is a mitigation for the case where GOMAXPROCS=1, because we won't ever observe a zero idle P count. It does mean that bgsweep is a little bit higher priority than before because it yields its time less often, so it could interfere with goroutine scheduling latencies more. However, by sweeping 10 spans before volunteering time, we directly reduce trace event production by 90% in all cases. The impact on scheduling latencies should be fairly minimal, as sweeping a span is already so fast, that sweeping 10 is unlikely to make a dent in any meaningful end-to-end latency. In fact, it may even improve application latencies overall by freeing up spans and sweep work from goroutines allocating memory. It may be worth considering pushing this number higher in the future. Another reason to do (2) is to reduce contention on npidle, which will be checked as part of (1), but this is a fairly minor concern. The main reason is to capture the GOMAXPROCS=1 case. Fixes #54767. Change-Id: I4361400f17197b8ab84c01f56203f20575b29fc6 Reviewed-on: https://go-review.googlesource.com/c/go/+/429615 TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Michael Knyszek <mknyszek@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2022-09-16runtime/metrics: add /sync/mutex/wait/total:seconds metricMichael Anthony Knyszek
This change adds a metric to the runtime/metrics package which tracks total mutex wait time for sync.Mutex and sync.RWMutex. The purpose of this metric is to be able to quickly get an idea of the total mutex wait time. The implementation of this metric piggybacks off of the existing G runnable tracking infrastructure, as well as the wait reason set on a G when it goes into _Gwaiting. Fixes #49881. Change-Id: I4691abf64ac3574bec69b4d7d4428b1573130517 Reviewed-on: https://go-review.googlesource.com/c/go/+/427618 Reviewed-by: Michael Pratt <mpratt@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-09-16runtime: set G wait reason more consistentlyMichael Anthony Knyszek
Currently, wait reasons are set somewhat inconsistently. In a follow-up CL, we're going to want to rely on the wait reason being there for casgstatus, so the status quo isn't really going to work for that. Plus this inconsistency means there are a whole bunch of cases where we could be more specific about the G's status but aren't. So, this change adds a new function, casGToWaiting which is like casgstatus but also sets the wait reason. The goal is that by using this API it'll be harder to forget to set a wait reason (or the lack thereof will at least be explicit). This change then updates all casgstatus(gp, ..., _Gwaiting) calls to casGToWaiting(gp, ..., waitReasonX) instead. For a number of these cases, we're missing a wait reason, and it wouldn't hurt to add a wait reason for them, so this change also adds those wait reasons. For #49881. Change-Id: Ia95e06ecb74ed17bb7bb94f1a362ebfe6bec1518 Reviewed-on: https://go-review.googlesource.com/c/go/+/427617 Reviewed-by: Michael Pratt <mpratt@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> Auto-Submit: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-09-07runtime: simplify code using unsafe.{Slice,String}cuiweixie
Updates #54854 Change-Id: Ie18665e93e477b6f220acf4c6c070b2af4343064 Reviewed-on: https://go-review.googlesource.com/c/go/+/428157 Run-TryBot: Ian Lance Taylor <iant@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com> Reviewed-by: Bryan Mills <bcmills@google.com> Auto-Submit: Ian Lance Taylor <iant@google.com>
2022-09-05runtime: refactor finalizer goroutine statusLeonard Wang
Use an atomic.Uint32 to represent the state of finalizer goroutine. fingStatus will only be changed to fingWake in non fingWait state, so it is safe to set fingRunningFinalizer status in runfinq. name old time/op new time/op delta Finalizer-8 592µs ± 4% 561µs ± 1% -5.22% (p=0.000 n=10+10) FinalizerRun-8 694ns ± 6% 675ns ± 7% ~ (p=0.059 n=9+8) Change-Id: I7e4da30cec98ce99f7d8cf4c97f933a8a2d1cae1 Reviewed-on: https://go-review.googlesource.com/c/go/+/400134 Reviewed-by: Joedian Reid <joedian@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Daniel Martí <mvdan@mvdan.cc> Reviewed-by: Michael Pratt <mpratt@google.com>
2022-09-05runtime: convert g.atomicstatus to internal atomic typeAndy Pan
Note that this changes some unsynchronized operations of g.atomicstatus to synchronized operations. Updates #53821 Change-Id: If249d62420ea09fbec39b570942f96c63669c333 Reviewed-on: https://go-review.googlesource.com/c/go/+/425363 TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Heschi Kreinick <heschi@google.com>
2022-09-01Revert "runtime: convert ncgocall to atomic type"Michael Pratt
This reverts CL 426075. Reason for revert: Import missing from cgocall.go. Change-Id: Iac17e914045b83da30484dbe2a624cde526fb175 Reviewed-on: https://go-review.googlesource.com/c/go/+/427614 Reviewed-by: Heschi Kreinick <heschi@google.com>
2022-09-01runtime: convert ncgocall to atomic typecuiweixie
For #53821 Change-Id: Ib0d62ee36487b3ed68e063976968f3cac6499e4b Reviewed-on: https://go-review.googlesource.com/c/go/+/426075 Reviewed-by: Michael Pratt <mpratt@google.com> Run-TryBot: xie cui <523516579@qq.com> Reviewed-by: Heschi Kreinick <heschi@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-08-31runtime: convert p.numTimers and p.deletedTimers to internal atomic typesAndy Pan
Note that this changes the non-atomic operations in p.destroy() to atomic operations. For #53821 Change-Id: I7bba77c9a2287ba697c87cce2c79293e4d1b3334 Reviewed-on: https://go-review.googlesource.com/c/go/+/425774 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2022-08-31runtime: convert extram and extraMWaiters to internal atomic typeAndy Pan
Updates #53821 Change-Id: Id579b2f8e48dfbe9f37e02d2fa8c94354f9887a4 Reviewed-on: https://go-review.googlesource.com/c/go/+/425480 Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Pratt <mpratt@google.com> Run-TryBot: hopehook <hopehook@golangcn.org> Auto-Submit: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-08-26runtime: convert forcegcstate.idle to internal atomic typeAndy Pan
Note that this changes a few unsynchronized operations of forcegcstate.idle to synchronized operations. Updates #53821 Change-Id: I041654cc84a188fad45e2df7abce3a434f9a1f15 Reviewed-on: https://go-review.googlesource.com/c/go/+/425361 Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2022-08-25runtime: convert netpollWaiters to internal atomic typeAndy Pan
Updates #53821 Change-Id: I8776382b3eb0b7752cfc0d9287b707039d3f05c6 Reviewed-on: https://go-review.googlesource.com/c/go/+/425358 Reviewed-by: Michael Pratt <mpratt@google.com> Run-TryBot: hopehook <hopehook@qq.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2022-08-18runtime: convert timer0When/timerModifiedEarliest to atomic.Int64Cuong Manh Le
So they match with when/nextwhen fields of timer struct. Updates #53821 Change-Id: Iad0cceb129796745774facfbbfe5756df3a320b4 Reviewed-on: https://go-review.googlesource.com/c/go/+/423117 Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com> Reviewed-by: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Keith Randall <khr@google.com> Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
2022-08-18runtime: convert m.cgoCallersUse to atomic typeCuong Manh Le
Updates #53821 Change-Id: I99b01f8e91b798e73275635c8a63fcdc4a8df9f1 Reviewed-on: https://go-review.googlesource.com/c/go/+/423888 Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Keith Randall <khr@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
2022-08-18runtime: convert p.timerModifiedEarliest to atomic typeCuong Manh Le
Updates #53821 Change-Id: Iac0d7a3871d9e3ee0ba38ee7ab989faca9c89666 Reviewed-on: https://go-review.googlesource.com/c/go/+/424397 Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com> Reviewed-by: Keith Randall <khr@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2022-08-17runtime: convert p.timer0When to atomic typeCuong Manh Le
Updates #53821 Change-Id: I523ec61116d290ecf7b7e3eb96e468695766cb4d Reviewed-on: https://go-review.googlesource.com/c/go/+/424396 Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com> Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com> Reviewed-by: Keith Randall <khr@google.com> Reviewed-by: Michael Pratt <mpratt@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-08-17runtime: convert freezing to atomic typeCuong Manh Le
Updates #53821 Change-Id: I77fcdb972b8920e1fb42248ce5bd2c3d2d0bd27e Reviewed-on: https://go-review.googlesource.com/c/go/+/423885 Reviewed-by: Michael Pratt <mpratt@google.com> Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Keith Randall <khr@google.com> Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>