[RFC] Performance Events 'Samples' report

From: Cliff Wickman
Date: Thu Feb 24 2011 - 19:14:46 EST


From: Cliff Wickman <cpw@xxxxxxx>

The perf command's report prints clock periods under the heading of 'Samples'.
Our applications people have been confused by this "Samples" heading.

perf report -n

# Overhead Samples Command Shared Object Symbol
# ........ .......... ............... .................... ................................
#
99.41%1522136216246 pthreads pthreads [.] work_function
0.33% 4980298302 perf [kernel.kallsyms] [k] clear_page_c
....

It would be more compact to print the number of samples. And that would
be consistent with the heading.

Below is the code that displays the periods. I don't see that the number
of samples is available here, but probably easily could be.
I presume that clock periods are derived from #samples * sample period.

perf/util/hist.c

640
641 if (symbol_conf.show_nr_samples) {
642 if (sep)
643 ret += snprintf(s + ret, size - ret, "%c%" PRIu64, *sep, period);
644 else
645 ret += snprintf(s + ret, size - ret, "%11" PRIu64, period);
646 }
647

Signed-off-by: Cliff Wickman <cpw@xxxxxxx>

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