b034905c82
When we collect a contextual profile, we sample the threads entering its root and only collect on one at a time (see `ContextRoot::Taken`). If we want to compare profiles between contextual profiles, and/or flat profiles, we have a problem: we don't know how to compare the counter values relative to each other. To that end, we add `ContextRoot::TotalEntries`, which is incremented every time a root is entered and serves as multiplier for the counter values collected under that root. We expose this in the profile and leave the normalization to the user of the profile, for a few reasons: * it's only needed if reasoning about all profiles in aggregate. * the goal, in compiler_rt, is to flush out the profile as quickly as possible, and performing multiplications adds an overhead that may not even be necessary if the consumer of the profile doesn't care about combining profiles * the information itself may be interesting as an indication of relative sampling of various contexts.
130 lines
5.0 KiB
LLVM
130 lines
5.0 KiB
LLVM
; REQUIRES: x86_64-linux
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; RUN: rm -rf %t
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; RUN: split-file %s %t
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; RUN: llvm-ctxprof-util fromYAML --input=%t/profile.yaml --output=%t/profile.ctxprofdata
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; RUN: opt -passes='module-inline,print<ctx-prof-analysis>' -ctx-profile-printer-level=everything %t/module.ll -S \
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; RUN: -use-ctx-profile=%t/profile.ctxprofdata -ctx-profile-printer-level=yaml \
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; RUN: -o - 2> %t/profile-final.yaml | FileCheck %s
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; RUN: diff %t/profile-final.yaml %t/expected.yaml
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; There are 2 calls to @a from @entrypoint. We only inline the one callsite
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; marked as alwaysinline, the rest are blocked (marked noinline). After the inline,
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; the updated contextual profile should still have the same tree for the non-inlined case.
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; For the inlined case, we should observe, for the @entrypoint context:
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; - an empty callsite where the inlined one was (first one, i.e. 0)
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; - more counters appended to the old counter list (because we ingested the
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; ones from @a). The values are copied.
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; - a new callsite to @b
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; CHECK-LABEL: @entrypoint
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; CHECK-LABEL: yes:
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; CHECK: call void @llvm.instrprof.increment(ptr @entrypoint, i64 0, i32 3, i32 1)
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; CHECK-NEXT: br label %loop.i
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; CHECK-LABEL: loop.i:
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; CHECK-NEXT: %indvar.i = phi i32 [ %indvar.next.i, %loop.i ], [ 0, %yes ]
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; CHECK-NEXT: call void @llvm.instrprof.increment(ptr @entrypoint, i64 0, i32 2, i32 3)
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; CHECK-NEXT: %b.i = add i32 %x, %indvar.i
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; CHECK-NEXT: call void @llvm.instrprof.callsite(ptr @entrypoint, i64 0, i32 1, i32 2, ptr @b)
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; CHECK-NEXT: %call3.i = call i32 @b() #1
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; CHECK-LABEL: no:
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; CHECK-NEXT: call void @llvm.instrprof.increment(ptr @entrypoint, i64 0, i32 3, i32 2)
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; CHECK-NEXT: call void @llvm.instrprof.callsite(ptr @entrypoint, i64 0, i32 2, i32 1, ptr @a)
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; CHECK-NEXT: %call2 = call i32 @a(i32 %x) #1
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; CHECK-NEXT: br label %exit
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; Make sure the postlink thinlto pipeline is aware of ctxprof
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; RUN: opt -passes='thinlto<O2>' -use-ctx-profile=%t/profile.ctxprofdata \
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; RUN: %t/module.ll -S -o - | FileCheck %s --check-prefix=PIPELINE
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; PIPELINE-LABEL: define i32 @entrypoint
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; PIPELINE-SAME: !prof ![[ENTRYPOINT_COUNT:[0-9]+]]
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; PIPELINE-LABEL: loop.i:
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; PIPELINE: br i1 %cond.i, label %loop.i, label %exit, !prof ![[LOOP_BW_INL:[0-9]+]]
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; PIPELINE-LABEL: define i32 @a
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; PIPELINE-LABEL: loop:
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; PIPELINE: br i1 %cond, label %loop, label %exit, !prof ![[LOOP_BW_ORIG:[0-9]+]]
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; PIPELINE: ![[ENTRYPOINT_COUNT]] = !{!"function_entry_count", i64 10}
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; These are the weights of the inlined @a, where the counters were 2, 100 (2 for entry, 100 for loop)
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; PIPELINE: ![[LOOP_BW_INL]] = !{!"branch_weights", i32 98, i32 2}
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; These are the weights of the un-inlined @a, where the counters were 8, 500 (8 for entry, 500 for loop)
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; PIPELINE: ![[LOOP_BW_ORIG]] = !{!"branch_weights", i32 492, i32 8}
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;--- module.ll
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define i32 @entrypoint(i32 %x) !guid !0 {
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call void @llvm.instrprof.increment(ptr @entrypoint, i64 0, i32 3, i32 0)
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%t = icmp eq i32 %x, 0
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br i1 %t, label %yes, label %no
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yes:
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call void @llvm.instrprof.increment(ptr @entrypoint, i64 0, i32 3, i32 1)
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call void @llvm.instrprof.callsite(ptr @entrypoint, i64 0, i32 2, i32 0, ptr @a)
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%call1 = call i32 @a(i32 %x) alwaysinline
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br label %exit
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no:
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call void @llvm.instrprof.increment(ptr @entrypoint, i64 0, i32 3, i32 2)
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call void @llvm.instrprof.callsite(ptr @entrypoint, i64 0, i32 2, i32 1, ptr @a)
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%call2 = call i32 @a(i32 %x) noinline
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br label %exit
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exit:
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%ret = phi i32 [%call1, %yes], [%call2, %no]
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ret i32 %ret
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}
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define i32 @a(i32 %x) !guid !1 {
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entry:
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call void @llvm.instrprof.increment(ptr @a, i64 0, i32 2, i32 0)
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br label %loop
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loop:
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%indvar = phi i32 [%indvar.next, %loop], [0, %entry]
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call void @llvm.instrprof.increment(ptr @a, i64 0, i32 2, i32 1)
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%b = add i32 %x, %indvar
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call void @llvm.instrprof.callsite(ptr @a, i64 0, i32 1, i32 0, ptr @b)
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%call3 = call i32 @b() noinline
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%indvar.next = add i32 %indvar, %call3
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%cond = icmp slt i32 %indvar.next, %x
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br i1 %cond, label %loop, label %exit
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exit:
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ret i32 8
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}
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define i32 @b() !guid !2 {
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call void @llvm.instrprof.increment(ptr @b, i64 0, i32 1, i32 0)
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ret i32 1
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}
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!0 = !{i64 1000}
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!1 = !{i64 1001}
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!2 = !{i64 1002}
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;--- profile.yaml
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Contexts:
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- Guid: 1000
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TotalRootEntryCount: 24
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Counters: [10, 2, 8]
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Callsites: -
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- Guid: 1001
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Counters: [2, 100]
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Callsites: -
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- Guid: 1002
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Counters: [100]
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-
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- Guid: 1001
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Counters: [8, 500]
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Callsites: -
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- Guid: 1002
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Counters: [500]
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;--- expected.yaml
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Contexts:
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- Guid: 1000
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TotalRootEntryCount: 24
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Counters: [ 10, 2, 8, 100 ]
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Callsites:
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- [ ]
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- - Guid: 1001
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Counters: [ 8, 500 ]
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Callsites:
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- - Guid: 1002
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Counters: [ 500 ]
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- - Guid: 1002
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Counters: [ 100 ]
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