diff options
Diffstat (limited to 'src/runtime/runtime2.go')
| -rw-r--r-- | src/runtime/runtime2.go | 77 |
1 files changed, 59 insertions, 18 deletions
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go index 5bd283d12f..0e0eb0b728 100644 --- a/src/runtime/runtime2.go +++ b/src/runtime/runtime2.go @@ -5,7 +5,6 @@ package runtime import ( - "internal/cpu" "runtime/internal/atomic" "runtime/internal/sys" "unsafe" @@ -413,14 +412,25 @@ type g struct { stackguard0 uintptr // offset known to liblink stackguard1 uintptr // offset known to liblink - _panic *_panic // innermost panic - offset known to liblink - _defer *_defer // innermost defer - m *m // current m; offset known to arm liblink - sched gobuf - syscallsp uintptr // if status==Gsyscall, syscallsp = sched.sp to use during gc - syscallpc uintptr // if status==Gsyscall, syscallpc = sched.pc to use during gc - stktopsp uintptr // expected sp at top of stack, to check in traceback - param unsafe.Pointer // passed parameter on wakeup + _panic *_panic // innermost panic - offset known to liblink + _defer *_defer // innermost defer + m *m // current m; offset known to arm liblink + sched gobuf + syscallsp uintptr // if status==Gsyscall, syscallsp = sched.sp to use during gc + syscallpc uintptr // if status==Gsyscall, syscallpc = sched.pc to use during gc + stktopsp uintptr // expected sp at top of stack, to check in traceback + // param is a generic pointer parameter field used to pass + // values in particular contexts where other storage for the + // parameter would be difficult to find. It is currently used + // in three ways: + // 1. When a channel operation wakes up a blocked goroutine, it sets param to + // point to the sudog of the completed blocking operation. + // 2. By gcAssistAlloc1 to signal back to its caller that the goroutine completed + // the GC cycle. It is unsafe to do so in any other way, because the goroutine's + // stack may have moved in the meantime. + // 3. By debugCallWrap to pass parameters to a new goroutine because allocating a + // closure in the runtime is forbidden. + param unsafe.Pointer atomicstatus uint32 stackLock uint32 // sigprof/scang lock; TODO: fold in to atomicstatus goid int64 @@ -452,6 +462,10 @@ type g struct { raceignore int8 // ignore race detection events sysblocktraced bool // StartTrace has emitted EvGoInSyscall about this goroutine + tracking bool // whether we're tracking this G for sched latency statistics + trackingSeq uint8 // used to decide whether to track this G + runnableStamp int64 // timestamp of when the G last became runnable, only used when tracking + runnableTime int64 // the amount of time spent runnable, cleared when running, only used when tracking sysexitticks int64 // cputicks when syscall has returned (for tracing) traceseq uint64 // trace event sequencer tracelastp puintptr // last P emitted an event for this goroutine @@ -483,17 +497,28 @@ type g struct { gcAssistBytes int64 } +// gTrackingPeriod is the number of transitions out of _Grunning between +// latency tracking runs. +const gTrackingPeriod = 8 + +const ( + // tlsSlots is the number of pointer-sized slots reserved for TLS on some platforms, + // like Windows. + tlsSlots = 6 + tlsSize = tlsSlots * sys.PtrSize +) + type m struct { g0 *g // goroutine with scheduling stack morebuf gobuf // gobuf arg to morestack divmod uint32 // div/mod denominator for arm - known to liblink // Fields not known to debuggers. - procid uint64 // for debuggers, but offset not hard-coded - gsignal *g // signal-handling g - goSigStack gsignalStack // Go-allocated signal handling stack - sigmask sigset // storage for saved signal mask - tls [6]uintptr // thread-local storage (for x86 extern register) + procid uint64 // for debuggers, but offset not hard-coded + gsignal *g // signal-handling g + goSigStack gsignalStack // Go-allocated signal handling stack + sigmask sigset // storage for saved signal mask + tls [tlsSlots]uintptr // thread-local storage (for x86 extern register) mstartfn func() curg *g // current running goroutine caughtsig guintptr // goroutine running during fatal signal @@ -537,10 +562,13 @@ type m struct { syscalltick uint32 freelink *m // on sched.freem - // mFixup is used to synchronize OS related m state (credentials etc) - // use mutex to access. + // mFixup is used to synchronize OS related m state + // (credentials etc) use mutex to access. To avoid deadlocks + // an atomic.Load() of used being zero in mDoFixupFn() + // guarantees fn is nil. mFixup struct { lock mutex + used uint32 fn func(bool) bool } @@ -605,6 +633,9 @@ type p struct { // unit and eliminates the (potentially large) scheduling // latency that otherwise arises from adding the ready'd // goroutines to the end of the run queue. + // + // Note that while other P's may atomically CAS this to zero, + // only the owner P can CAS it to a valid G. runnext guintptr // Available G's (status == Gdead) @@ -713,7 +744,8 @@ type p struct { // scheduler ASAP (regardless of what G is running on it). preempt bool - pad cpu.CacheLinePad + // Padding is no longer needed. False sharing is now not a worry because p is large enough + // that its size class is an integer multiple of the cache line size (for any of our architectures). } type schedt struct { @@ -803,6 +835,15 @@ type schedt struct { // Acquire and hold this mutex to block sysmon from interacting // with the rest of the runtime. sysmonlock mutex + + _ uint32 // ensure timeToRun has 8-byte alignment + + // timeToRun is a distribution of scheduling latencies, defined + // as the sum of time a G spends in the _Grunnable state before + // it transitions to _Grunning. + // + // timeToRun is protected by sched.lock. + timeToRun timeHistogram } // Values for the flags field of a sigTabT. @@ -1105,5 +1146,5 @@ var ( isarchive bool // -buildmode=c-archive ) -// Must agree with cmd/internal/objabi.Framepointer_enabled. +// Must agree with internal/buildcfg.Experiment.FramePointer. const framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64" |