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81 lines
2.2 KiB
Markdown
81 lines
2.2 KiB
Markdown
# Perf benchmark
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### Overview
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- Using <i>perf_event_open</i> to get hardware and software counters.
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- Only useful when you want to measure something inside the code really quick.
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Otherwise, use <i>perf</i> itself.
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- Linux only.
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- All predefined hardware and software counters are generated in the header
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file, you can uncomment counters as you wish.
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- If some counters or combination of counters doesn't work or doesn't work as
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expected, please check out performance counter register allocation
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documentation for your CPU. CPUs have limited registers for performance
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counters and some counters can use specific registers only.
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- Golang version : https://github.com/tezc/goperf
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#### Usage
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```c
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#include "sc_perf.h"
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int main(int argc, char *argv[])
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{
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sc_perf_start();
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long_running_operation();
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sc_perf_end();
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return 0;
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}
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```
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##### Output will be like
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```
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| Event | Value | Measurement time
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---------------------------------------------------------------
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| time (seconds) | 0.66 | (100,00%)
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| cpu-clock | 654075766.00 | (100.00%)
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| task-clock | 654077198.00 | (100.00%)
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| page-faults | 3.00 | (100.00%)
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| context-switches | 46.00 | (100.00%)
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| cpu-migrations | 0.00 | (100.00%)
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| page-fault-minor | 3.00 | (100.00%)
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| cpu-cycles | 2656529748.00 | (100.00%)
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| instructions | 7589235720.00 | (100.00%)
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| cache-misses | 28715.00 | (100.00%)
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| L1D-read-miss | 34124.00 | (100.00%)
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| L1I-read-miss | 121958.00 | (100.00%)
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```
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##### Pause example
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```c
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#include "sc_perf.h"
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int main(int argc, char *argv[])
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{
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sc_perf_start();
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long_running_operation();
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//Will stop counters.
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sc_perf_pause();
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operation_you_dont_want_to_measure();
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//Start counters again.
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sc_perf_start();
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another_long_running_operation();
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sc_perf_end();
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sc_perf_start();
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some_other_long_running_operation();
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sc_perf_end();
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return 0;
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}
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``` |