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2018-11-02runtime: avoid runtimeNano call on a common netpoll pathDmitry Vyukov
runtimeNano is slower than nanotime, so pass the duration to runtime_pollSetDeadline as is. netpoll can add nanotime itself. Arguably a bit simpler because, say, a negative duration clearly represents already expired timer, no need to compare to nanotime again. This may also fix an obscure corner case when a deadline in past which happens to be nanotime 0 is confused with no deadline at all, which are radically different things. Also don't compute any durations and times if Time is zero (currently we first compute everything and then reset d back to 0, which is wasteful). name old time/op new time/op delta TCP4OneShotTimeout-6 17.1µs ± 0% 17.0µs ± 0% ~ (p=0.421 n=5+5) SetReadDeadline-6 230ns ± 0% 205ns ± 1% -10.63% (p=0.008 n=5+5) Change-Id: I2aad699270289a5b9ead68f5e44ec4ec6d96baa0 Reviewed-on: https://go-review.googlesource.com/c/146344 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
2018-11-02runtime: execute memory barrier conditionally when changing netpoll timersDmitry Vyukov
We only need the memory barrier in poll_runtime_pollSetDeadline only when one of the timers has fired, which is not the expected case. Memory barrier can be somewhat expensive on some archs, so execute it only if one of the timers has in fact fired. name old time/op new time/op delta TCP4OneShotTimeout-6 17.0µs ± 0% 17.1µs ± 0% +0.35% (p=0.032 n=5+5) SetReadDeadline-6 232ns ± 0% 230ns ± 0% -1.03% (p=0.000 n=4+5) Update #25729 Change-Id: Ifce6f505b9e7ba3717bad8f454077a2e94ea6e75 Reviewed-on: https://go-review.googlesource.com/c/146343 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-11-02runtime: add and use modtimer in netpollDmitry Vyukov
Currently when netpoll deadline is incrementally prolonged, we delete and re-add timer each time. Add modtimer function that does both and use it when we need to modify an existing netpoll timer to avoid unnecessary lock/unlock. TCP4OneShotTimeout-6 17.2µs ± 0% 17.0µs ± 0% -0.82% (p=0.008 n=5+5) SetReadDeadline-6 274ns ± 2% 261ns ± 0% -4.89% (p=0.008 n=5+5) Update #25729 Change-Id: I08b89dbbc1785dd180e967a37b0aa23b0c4613a8 Reviewed-on: https://go-review.googlesource.com/c/146339 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-11-02runtime: don't recreate netpoll timers if they don't changeDmitry Vyukov
Currently we always delete both read and write timers and then add them again. However, if user setups read and write deadline separately, then we don't need to touch the other one. name old time/op new time/op delta TCP4OneShotTimeout-6 17.2µs ± 0% 17.2µs ± 0% ~ (p=0.310 n=5+5) SetReadDeadline-6 319ns ± 1% 274ns ± 2% -13.94% (p=0.008 n=5+5) Update #25729 Change-Id: I4c869c3083521de6d0cd6ca99a7609d4dd84b4e4 Reviewed-on: https://go-review.googlesource.com/c/146338 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-10-03runtime: add AIX operating systemClément Chigot
This commit adds AIX operating system to runtime package for ppc64 architecture. Only new files and minor changes are in this commit. Others modifications in files like asm_ppc64.s will be in separate commits. Updates: #25893 Change-Id: I9c5e073f5f3debb43b004ad1167694a5afd31cfd Reviewed-on: https://go-review.googlesource.com/c/138716 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-08-20runtime: use gList in netpollAustin Clements
netpoll is perhaps one of the most confusing uses of G lists currently since it passes around many lists as bare *g values right now. Switching to gList makes it much clearer what's an individual g and what's a list. Change-Id: I8d8993c4967c5bae049c7a094aad3a657928ba6c Reviewed-on: https://go-review.googlesource.com/129397 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Rick Hudson <rlh@golang.org>
2018-06-04net: add js/wasm architectureRichard Musiol
This commit adds the js/wasm architecture to the net package. The net package is not supported by js/wasm, but a simple fake networking is available so tests of other packages that require basic TCP sockets can pass. The tests of the net package itself are mostly disabled. Updates #18892 Change-Id: Id287200c39f0a3e23d20ef17260ca15ccdcca032 Reviewed-on: https://go-review.googlesource.com/109995 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-05-03runtime: convert g.waitreason from string to uint8Josh Bleecher Snyder
Every time I poke at #14921, the g.waitreason string pointer writes show up. They're not particularly important performance-wise, but it'd be nice to clear the noise away. And it does open up a few extra bytes in the g struct for some future use. This is a re-roll of CL 99078, which was rolled back because of failures on s390x. Those failures were apparently due to an old version of gdb. Change-Id: Icc2c12f449b2934063fd61e272e06237625ed589 Reviewed-on: https://go-review.googlesource.com/111256 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Michael Munday <mike.munday@ibm.com>
2018-03-13Revert "runtime: convert g.waitreason from string to uint8"Josh Bleecher Snyder
This reverts commit 4eea887fd477368653f6fcf8ad766030167936e5. Reason for revert: broke s390x build Change-Id: Id6c2b6a7319273c4d21f613d4cdd38b00d49f847 Reviewed-on: https://go-review.googlesource.com/100375 Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2018-03-12runtime: convert g.waitreason from string to uint8Josh Bleecher Snyder
Every time I poke at #14921, the g.waitreason string pointer writes show up. They're not particularly important performance-wise, but it'd be nice to clear the noise away. And it does open up a few extra bytes in the g struct for some future use. Change-Id: I7ffbd52fbc2a286931a2218038fda52ed6473cc9 Reviewed-on: https://go-review.googlesource.com/99078 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
2017-04-25runtime: adjust netpoll panic messagesMikio Hara
Change-Id: I34547b057605bb9e1e2227c41867589348560244 Reviewed-on: https://go-review.googlesource.com/41513 Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-02-15os: use poller for file I/OIan Lance Taylor
This changes the os package to use the runtime poller for file I/O where possible. When a system call blocks on a pollable descriptor, the goroutine will be blocked on the poller but the thread will be released to run other goroutines. When using a non-pollable descriptor, the os package will continue to use thread-blocking system calls as before. For example, on GNU/Linux, the runtime poller uses epoll. epoll does not support ordinary disk files, so they will continue to use blocking I/O as before. The poller will be used for pipes. Since this means that the poller is used for many more programs, this modifies the runtime to only block waiting for the poller if there is some goroutine that is waiting on the poller. Otherwise, there is no point, as the poller will never make any goroutine ready. This preserves the runtime's current simple deadlock detection. This seems to crash FreeBSD systems, so it is disabled on FreeBSD. This is issue 19093. Using the poller on Windows requires opening the file with FILE_FLAG_OVERLAPPED. We should only do that if we can remove that flag if the program calls the Fd method. This is issue 19098. Update #6817. Update #7903. Update #15021. Update #18507. Update #19093. Update #19098. Change-Id: Ia5197dcefa7c6fbcca97d19a6f8621b2abcbb1fe Reviewed-on: https://go-review.googlesource.com/36800 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
2017-02-13net: refactor poller into new internal/poll packageIan Lance Taylor
This will make it possible to use the poller with the os package. This is a lot of code movement but the behavior is intended to be unchanged. Update #6817. Update #7903. Update #15021. Update #18507. Change-Id: I1413685928017c32df5654ded73a2643820977ae Reviewed-on: https://go-review.googlesource.com/36799 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Crawshaw <crawshaw@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
2016-10-15runtime: mark several types go:notinheapAustin Clements
This covers basically all sysAlloc'd, persistentalloc'd, and fixalloc'd types. Change-Id: I0487c887c2a0ade5e33d4c4c12d837e97468e66b Reviewed-on: https://go-review.googlesource.com/30941 Reviewed-by: Rick Hudson <rlh@golang.org>
2016-03-07runtime: eliminate unnecessary type conversionsMatthew Dempsky
Automated refactoring produced using github.com/mdempsky/unconvert. Change-Id: Iacf871a4f221ef17f48999a464ab2858b2bbaa90 Reviewed-on: https://go-review.googlesource.com/20071 Reviewed-by: Austin Clements <austin@google.com> Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-11-10runtime: break atomics out into package runtime/internal/atomicMichael Matloob
This change breaks out most of the atomics functions in the runtime into package runtime/internal/atomic. It adds some basic support in the toolchain for runtime packages, and also modifies linux/arm atomics to remove the dependency on the runtime's mutex. The mutexes have been replaced with spinlocks. all trybots are happy! In addition to the trybots, I've tested on the darwin/arm64 builder, on the darwin/arm builder, and on a ppc64le machine. Change-Id: I6698c8e3cf3834f55ce5824059f44d00dc8e3c2f Reviewed-on: https://go-review.googlesource.com/14204 Run-TryBot: Michael Matloob <matloob@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
2015-06-11all: fix misprints in commentsAinar Garipov
These were found by grepping the comments from the go code and feeding the output to aspell. Change-Id: Id734d6c8d1938ec3c36bd94a4dbbad577e3ad395 Reviewed-on: https://go-review.googlesource.com/10941 Reviewed-by: Aamir Khan <syst3m.w0rm@gmail.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-04-20runtime: replace func-based write barrier skipping with type-basedRuss Cox
This CL revises CL 7504 to use explicitly uintptr types for the struct fields that are going to be updated sometimes without write barriers. The result is that the fields are now updated *always* without write barriers. This approach has two important properties: 1) Now the GC never looks at the field, so if the missing reference could cause a problem, it will do so all the time, not just when the write barrier is missed at just the right moment. 2) Now a write barrier never happens for the field, avoiding the (correct) detection of inconsistent write barriers when GODEBUG=wbshadow=1. Change-Id: Iebd3962c727c0046495cc08914a8dc0808460e0e Reviewed-on: https://go-review.googlesource.com/9019 Reviewed-by: Austin Clements <austin@google.com> Run-TryBot: Russ Cox <rsc@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-03-17runtime: Remove write barriers during STW.Rick Hudson
The GC assumes that there will be no asynchronous write barriers when the world is stopped. This keeps the synchronization between write barriers and the GC simple. However, currently, there are a few places in runtime code where this assumption does not hold. The GC stops the world by collecting all Ps, which stops all user Go code, but small parts of the runtime can run without a P. For example, the code that releases a P must still deschedule its G onto a runnable queue before stopping. Similarly, when a G returns from a long-running syscall, it must run code to reacquire a P. Currently, this code can contain write barriers. This can lead to the GC collecting reachable objects if something like the following sequence of events happens: 1. GC stops the world by collecting all Ps. 2. G #1 returns from a syscall (for example), tries to install a pointer to object X, and calls greyobject on X. 3. greyobject on G #1 marks X, but does not yet add it to a write buffer. At this point, X is effectively black, not grey, even though it may point to white objects. 4. GC reaches X through some other path and calls greyobject on X, but greyobject does nothing because X is already marked. 5. GC completes. 6. greyobject on G #1 adds X to a work buffer, but it's too late. 7. Objects that were reachable only through X are incorrectly collected. To fix this, we check the invariant that no asynchronous write barriers happen when the world is stopped by checking that write barriers always have a P, and modify all currently known sources of these writes to disable the write barrier. In all modified cases this is safe because the object in question will always be reachable via some other path. Some of the trace code was turned off, in particular the code that traces returning from a syscall. The GC assumes that as far as the heap is concerned the thread is stopped when it is in a syscall. Upon returning the trace code must not do any heap writes for the same reasons discussed above. Fixes #10098 Fixes #9953 Fixes #9951 Fixes #9884 May relate to #9610 #9771 Change-Id: Ic2e70b7caffa053e56156838eb8d89503e3c0c8a Reviewed-on: https://go-review.googlesource.com/7504 Reviewed-by: Austin Clements <austin@google.com>
2015-03-10runtime: remove runtime frames from stacks in tracesDmitry Vyukov
Stip uninteresting bottom and top frames from trace stacks. This makes both binary and json trace files smaller, and also makes stacks shorter and more readable in the viewer. Change-Id: Ib9c80ccc280504f0e235f867f53f1d2652c41583 Reviewed-on: https://go-review.googlesource.com/5523 Reviewed-by: Keith Randall <khr@golang.org> Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
2015-01-28runtime: add tracing of runtime eventsDmitry Vyukov
Add actual tracing of interesting runtime events. Part of a larger tracing functionality: https://docs.google.com/document/u/1/d/1FP5apqzBgr7ahCCgFO-yoVhk4YZrNIDNf9RybngBc14/pub Full change: https://codereview.appspot.com/146920043 Change-Id: Icccf54aea54e09350bb698ba6bf11532f9fbe6d3 Reviewed-on: https://go-review.googlesource.com/1451 Reviewed-by: Russ Cox <rsc@golang.org>
2015-01-14runtime: fix spurious deadlock in netpollDmitry Vyukov
There is a small possibility that runtime deadlocks when netpoll is just activated. Consider the following scenario: GOMAXPROCS=1 epfd=-1 (netpoll is not activated yet) A thread is in findrunnable, sets sched.lastpoll=0, calls netpoll(true), which returns nil. Now the thread is descheduled for some time. Then sysmon retakes a P from syscall and calls handoffp. The "If this is the last running P and nobody is polling network" check in handoffp fails, since the first thread set sched.lastpoll=0. So handoffp decides that there is already a thread that polls network and so it calls pidleput. Now the first thread is scheduled again, finds no work and calls stopm. There is no thread that polls network and so checkdead reports deadlock. To fix this, don't set sched.lastpoll=0 when netpoll is not activated. The deadlock can happen if cgo is disabled (-tag=netgo) and only on program startup (when netpoll is just activated). The test is from issue 5216 that lead to addition of the "If this is the last running P and nobody is polling network" check in handoffp. Update issue 9576. Change-Id: I9405f627a4d37bd6b99d5670d4328744aeebfc7a Reviewed-on: https://go-review.googlesource.com/2750 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2014-12-28runtime: rename gothrow to throwKeith Randall
Rename "gothrow" to "throw" now that the C version of "throw" is no longer needed. This change is purely mechanical except in panic.go where the old version of "throw" has been deleted. sed -i "" 's/[[:<:]]gothrow[[:>:]]/throw/g' runtime/*.go Change-Id: Icf0752299c35958b92870a97111c67bcd9159dc3 Reviewed-on: https://go-review.googlesource.com/2150 Reviewed-by: Minux Ma <minux@golang.org> Reviewed-by: Dave Cheney <dave@cheney.net>
2014-12-23runtime: remove thunk.sRuss Cox
Replace with uses of //go:linkname in Go files, direct use of name in .s files. The only one that really truly needs a jump is reflect.call; the jump is now next to the runtime.reflectcall assembly implementations. Change-Id: Ie7ff3020a8f60a8e4c8645fe236e7883a3f23f46 Reviewed-on: https://go-review.googlesource.com/1962 Reviewed-by: Austin Clements <austin@google.com>
2014-11-13[dev.cc] runtime: convert Solaris port to GoAram Hăvărneanu
Memory management was consolitated with the BSD ports, since it was almost identical. Assembly thunks are gone, being replaced by the new //go:linkname feature. This change supersedes CL 138390043 (runtime: convert solaris netpoll to Go), which was previously reviewed and tested. This change is only the first step, the port now builds, but doesn't run. Binaries fail to exec: ld.so.1: 6.out: fatal: 6.out: TLS requirement failure : TLS support is unavailable Killed This seems to happen because binaries don't link with libc.so anymore. We will have to solve that in a different CL. Also this change is just a rough translation of the original C code, cleanup will come in a different CL. [This CL is part of the removal of C code from package runtime. See golang.org/s/dev.cc for an overview.] LGTM=rsc R=rsc, dave CC=golang-codereviews, iant, khr, minux, r, rlh https://golang.org/cl/174960043
2014-11-12[dev.cc] runtime: delete scalararg, ptrarg; rename onM to systemstackRuss Cox
Scalararg and ptrarg are not "signal safe". Go code filling them out can be interrupted by a signal, and then the signal handler runs, and if it also ends up in Go code that uses scalararg or ptrarg, now the old values have been smashed. For the pieces of code that do need to run in a signal handler, we introduced onM_signalok, which is really just onM except that the _signalok is meant to convey that the caller asserts that scalarg and ptrarg will be restored to their old values after the call (instead of the usual behavior, zeroing them). Scalararg and ptrarg are also untyped and therefore error-prone. Go code can always pass a closure instead of using scalararg and ptrarg; they were only really necessary for C code. And there's no more C code. For all these reasons, delete scalararg and ptrarg, converting the few remaining references to use closures. Once those are gone, there is no need for a distinction between onM and onM_signalok, so replace both with a single function equivalent to the current onM_signalok (that is, it can be called on any of the curg, g0, and gsignal stacks). The name onM and the phrase 'm stack' are misnomers, because on most system an M has two system stacks: the main thread stack and the signal handling stack. Correct the misnomer by naming the replacement function systemstack. Fix a few references to "M stack" in code. The main motivation for this change is to eliminate scalararg/ptrarg. Rick and I have already seen them cause problems because the calling sequence m.ptrarg[0] = p is a heap pointer assignment, so it gets a write barrier. The write barrier also uses onM, so it has all the same problems as if it were being invoked by a signal handler. We worked around this by saving and restoring the old values and by calling onM_signalok, but there's no point in keeping this nice home for bugs around any longer. This CL also changes funcline to return the file name as a result instead of filling in a passed-in *string. (The *string signature is left over from when the code was written in and called from C.) That's arguably an unrelated change, except that once I had done the ptrarg/scalararg/onM cleanup I started getting false positives about the *string argument escaping (not allowed in package runtime). The compiler is wrong, but the easiest fix is to write the code like Go code instead of like C code. I am a bit worried that the compiler is wrong because of some use of uninitialized memory in the escape analysis. If that's the reason, it will go away when we convert the compiler to Go. (And if not, we'll debug it the next time.) LGTM=khr R=r, khr CC=austin, golang-codereviews, iant, rlh https://golang.org/cl/174950043
2014-11-11[dev.cc] runtime: convert scheduler from C to GoRuss Cox
The conversion was done with an automated tool and then modified only as necessary to make it compile and run. [This CL is part of the removal of C code from package runtime. See golang.org/s/dev.cc for an overview.] LGTM=r R=r, daniel.morsing CC=austin, dvyukov, golang-codereviews, iant, khr https://golang.org/cl/172260043
2014-09-08build: move package sources from src/pkg to srcRuss Cox
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.