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I'd like perf to output raw sample counts rather than percentages. This is useful for determining whether I've sped up a function I'm trying to optimize.
To be clear, I'd like to do something like
perf record ./a.out
perf report
and see how many times perf sampled each function in a.out.
Shark can do this on Mac, as can (I believe) Xperf. Is this possible on Linux with perf?
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The perf command is used as a primary interface to the Linux kernel performance monitoring capabilities and can record CPU performance counters and trace points.
A perf record command was used to trace the block:block_rq_issue probe, which fires when a block device I/O request is issued (disk I/O). Options included -a to trace all CPUs, and -g to capture call graphs (stack traces). Trace data is written to a perf. data file, and tracing ended when Ctrl-C was hit.
Sampling with perf record The report contains 4 columns, which have their own specific meaning: Overhead: the percentage of overall samples collected in the corresponding function. Command: the command to which the samples belong.
perf report (version 2.6.35.7) now supports the -n flag, which does what I want.
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