73eb9b3314
The `llvm-profdata order` command is used to compute a function order using traces from the input profile. Add the `--num-test-traces` flag to keep aside N traces to evalute this order. These test traces are assumed to be the actual function execution order in some experiment. The output is a number that represents how many page faults we got. Lower is better. I tested on a large profile I already had. ``` llvm-profdata order default.profdata --num-test-traces=30 # Ordered 149103 functions # Total area under the page fault curve: 2.271827e+09 ... ``` I also improved `TemporalProfTraceTy::createBPFunctionNodes()` in a few ways: * Simplified how `UN`s are computed * Change how the initial `Node` order is computed * Filter out rare and common `UN`s * Output vector is an aliased argument instead of a return These changes slightly improved the evaluation in my test. ``` llvm-profdata order default.profdata --num-test-traces=30 # Ordered 149103 functions # Total area under the page fault curve: 2.268586e+09 ... ```
52 lines
476 B
Plaintext
52 lines
476 B
Plaintext
# RUN: llvm-profdata order %s --num-test-traces=1 | FileCheck %s
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# CHECK: # Total area under the page fault curve: 4.000000e+00
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# CHECK: a
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# CHECK: b
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# CHECK: c
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# CHECK: x
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# Header
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:ir
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:temporal_prof_traces
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# Num Traces
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4
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# Trace Stream Size:
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4
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# Weight
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1
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a, main.c:b, c
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# Weight
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1
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a, x, main.c:b, c
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# Weight
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1
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a, main.c:b, c
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# Weight
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1
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a, main.c:b, c, x
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a
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# Func Hash:
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0x1234
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# Num Counters:
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1
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# Counter Values:
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101
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main.c:b
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0x5678
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1
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202
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c
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0xabcd
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1
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303
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x
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0xefff
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1
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404
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