diff options
Diffstat (limited to 'libgo/go/runtime/runtime2.go')
| -rw-r--r-- | libgo/go/runtime/runtime2.go | 52 |
1 files changed, 41 insertions, 11 deletions
diff --git a/libgo/go/runtime/runtime2.go b/libgo/go/runtime/runtime2.go index 1879b829be7..81a40d5633e 100644 --- a/libgo/go/runtime/runtime2.go +++ b/libgo/go/runtime/runtime2.go @@ -5,7 +5,6 @@ package runtime import ( - "internal/cpu" "runtime/internal/atomic" "runtime/internal/sys" "unsafe" @@ -412,7 +411,18 @@ type g struct { syscallsp uintptr // if status==Gsyscall, syscallsp = sched.sp to use during gc syscallpc uintptr // if status==Gsyscall, syscallpc = sched.pc to use during gc // Not for gccgo: stktopsp uintptr // expected sp at top of stack, to check in traceback - param unsafe.Pointer // passed parameter on wakeup + // 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 // Not for gccgo: stackLock uint32 // sigprof/scang lock; TODO: fold in to atomicstatus goid int64 @@ -446,6 +456,10 @@ 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 @@ -529,6 +543,17 @@ type g struct { stackcontext [10]uintptr // split-stack context } +// 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 // Not for gccgo: morebuf gobuf // gobuf arg to morestack @@ -539,7 +564,7 @@ type m struct { gsignal *g // signal-handling g // Not for gccgo: goSigStack gsignalStack // Go-allocated signal handling stack sigmask sigset // storage for saved signal mask - // Not for gccgo: tls [6]uintptr // thread-local storage (for x86 extern register) + // Not for gccgo: tls [tlsSlots]uintptr // thread-local storage (for x86 extern register) mstartfn func() curg *g // current running goroutine caughtsig guintptr // goroutine running during fatal signal @@ -663,6 +688,9 @@ 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) @@ -708,7 +736,7 @@ type p struct { // timerModifiedEarlier status. Because the timer may have been // modified again, there need not be any timer with this value. // This is updated using atomic functions. - // This is 0 if the value is unknown. + // This is 0 if there are no timerModifiedEarlier timers. timerModifiedEarliest uint64 // Per-P GC state @@ -754,12 +782,6 @@ type p struct { // Modified using atomic instructions. numTimers uint32 - // Number of timerModifiedEarlier timers on P's heap. - // This should only be modified while holding timersLock, - // or while the timer status is in a transient state - // such as timerModifying. - adjustTimers uint32 - // Number of timerDeleted timers in P's heap. // Modified using atomic instructions. deletedTimers uint32 @@ -771,7 +793,8 @@ 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 { @@ -860,6 +883,13 @@ type schedt struct { // Acquire and hold this mutex to block sysmon from interacting // with the rest of the runtime. sysmonlock mutex + + // 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. |