cmd/compile: use CDF to determine PGO inline threshold

Currently in PGO we use a percentage threshold to determine if a
callsite is hot. This CL uses a different method -- treating the
hottest callsites that make up cumulatively top X% of total edge
weights as hot (X=95 for now). This default might work better for
a wider range of profiles. (The absolute threshold can still be
changed by a flag.)

For #55022.

Change-Id: I7e3b6f0c3cf23f9a89dd5994c10075b498bf14ee
Reviewed-on: https://go-review.googlesource.com/c/go/+/447016
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
This commit is contained in:
Cherry Mui 2022-11-01 12:33:58 -04:00
parent 932330fdbf
commit b07e845e76
2 changed files with 79 additions and 39 deletions

View file

@ -16,39 +16,39 @@ var Debug DebugFlags
// The -d option takes a comma-separated list of settings.
// Each setting is name=value; for ints, name is short for name=1.
type DebugFlags struct {
Append int `help:"print information about append compilation"`
Checkptr int `help:"instrument unsafe pointer conversions\n0: instrumentation disabled\n1: conversions involving unsafe.Pointer are instrumented\n2: conversions to unsafe.Pointer force heap allocation"`
Closure int `help:"print information about closure compilation"`
DclStack int `help:"run internal dclstack check"`
Defer int `help:"print information about defer compilation"`
DisableNil int `help:"disable nil checks"`
DumpPtrs int `help:"show Node pointers values in dump output"`
DwarfInl int `help:"print information about DWARF inlined function creation"`
Export int `help:"print export data"`
GCProg int `help:"print dump of GC programs"`
Gossahash string `help:"hash value for use in debugging the compiler"`
InlFuncsWithClosures int `help:"allow functions with closures to be inlined"`
Libfuzzer int `help:"enable coverage instrumentation for libfuzzer"`
LocationLists int `help:"print information about DWARF location list creation"`
Nil int `help:"print information about nil checks"`
NoOpenDefer int `help:"disable open-coded defers"`
NoRefName int `help:"do not include referenced symbol names in object file"`
PCTab string `help:"print named pc-value table\nOne of: pctospadj, pctofile, pctoline, pctoinline, pctopcdata"`
Panic int `help:"show all compiler panics"`
Reshape int `help:"print information about expression reshaping"`
Shapify int `help:"print information about shaping recursive types"`
Slice int `help:"print information about slice compilation"`
SoftFloat int `help:"force compiler to emit soft-float code"`
SyncFrames int `help:"how many writer stack frames to include at sync points in unified export data"`
TypeAssert int `help:"print information about type assertion inlining"`
TypecheckInl int `help:"eager typechecking of inline function bodies"`
Unified int `help:"enable unified IR construction"`
WB int `help:"print information about write barriers"`
ABIWrap int `help:"print information about ABI wrapper generation"`
MayMoreStack string `help:"call named function before all stack growth checks"`
InlineHotCallSiteThreshold string `help:"threshold percentage for determining call sites as hot candidates for inlining"`
InlineHotBudget int `help:"inline budget for hot functions"`
PGOInline int `help:"debug profile-guided inlining"`
Append int `help:"print information about append compilation"`
Checkptr int `help:"instrument unsafe pointer conversions\n0: instrumentation disabled\n1: conversions involving unsafe.Pointer are instrumented\n2: conversions to unsafe.Pointer force heap allocation"`
Closure int `help:"print information about closure compilation"`
DclStack int `help:"run internal dclstack check"`
Defer int `help:"print information about defer compilation"`
DisableNil int `help:"disable nil checks"`
DumpPtrs int `help:"show Node pointers values in dump output"`
DwarfInl int `help:"print information about DWARF inlined function creation"`
Export int `help:"print export data"`
GCProg int `help:"print dump of GC programs"`
Gossahash string `help:"hash value for use in debugging the compiler"`
InlFuncsWithClosures int `help:"allow functions with closures to be inlined"`
Libfuzzer int `help:"enable coverage instrumentation for libfuzzer"`
LocationLists int `help:"print information about DWARF location list creation"`
Nil int `help:"print information about nil checks"`
NoOpenDefer int `help:"disable open-coded defers"`
NoRefName int `help:"do not include referenced symbol names in object file"`
PCTab string `help:"print named pc-value table\nOne of: pctospadj, pctofile, pctoline, pctoinline, pctopcdata"`
Panic int `help:"show all compiler panics"`
Reshape int `help:"print information about expression reshaping"`
Shapify int `help:"print information about shaping recursive types"`
Slice int `help:"print information about slice compilation"`
SoftFloat int `help:"force compiler to emit soft-float code"`
SyncFrames int `help:"how many writer stack frames to include at sync points in unified export data"`
TypeAssert int `help:"print information about type assertion inlining"`
TypecheckInl int `help:"eager typechecking of inline function bodies"`
Unified int `help:"enable unified IR construction"`
WB int `help:"print information about write barriers"`
ABIWrap int `help:"print information about ABI wrapper generation"`
MayMoreStack string `help:"call named function before all stack growth checks"`
InlineHotCallSiteCDFThreshold string `help:"cummulative threshold percentage for determining call sites as hot candidates for inlining"`
InlineHotBudget int `help:"inline budget for hot functions"`
PGOInline int `help:"debug profile-guided inlining"`
ConcurrentOk bool // true if only concurrentOk flags seen
}