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SubjectRe: [PATCH] perf, tools: Support spark lines in perf stat v2
On Mon, May 12, 2014 at 04:01:26PM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
>
> perf stat -rX prints the stddev for multiple measurements.
> Just looking at the stddev for judging the quality of the data
> is a bit dangerous The simplest sanity check is to just look
> at a simple plot. This patchs add a sparkline to the end
> of the measurements to make it simple to judge the data.
>
> The sparkline only uses UTF-8, so should be readable
> in all modern tools and terminals.
>
> The sparkline is between the minimum and maximum of the data,
> so it's mainly a indicator of variance. To keep the code
> simple and make the output not too wide only the first
> 8 values are printed. If more values are there it adds '..'
>
> The code is inspired by Zach Holman's spark shell script.
>
> Example output (view in non-proportial font):
>
> Performance counter stats for 'true' (10 runs):
>
> 0.175672 task-clock (msec) # 0.555 CPUs utilized ( +- 1.77% ) █▄▁▁▁▁▁▁..
> 0 context-switches # 0.000 K/sec
> 0 cpu-migrations # 0.000 K/sec
> 114 page-faults # 0.647 M/sec ( +- 0.14% ) ▁█▁▁████..
> 520,798 cycles # 2.965 GHz ( +- 1.75% ) █▄▁▁▁▁▁▁..
> 433,525 instructions # 0.83 insns per cycle ( +- 0.28% ) ▅▇▅▄▇█▁▆..
> 83,012 branches # 472.537 M/sec ( +- 0.31% ) ▅▇▆▄▇█▁▆..
> 3,157 branch-misses # 3.80% of all branches ( +- 2.55% ) ▇█▃▅▁▃▁▂..
>
> 0.000316660 seconds time elapsed ( +- 1.78% ) █▅▁▁▁▁▁▁..
>
> As you can see even in the most simple run there are quite interesting
> patterns. The time sparkline suggests it would be also useful to have an option
> to throw the first measurement away.
>
> Known issues:
> - Makes the perf stat output wider. Could be adjust by shrinking
> some white space. Not done so far.
> - No output for -A/--per-socket/--per-core with -rX. This code
> is missing the basic noise detection code. Once it's added there
> sparklines could be shown too.
>
> v2: Address review feedback. Use all_zero() and remove len.

ok.. confusing.. so this v2 has changes which are missing in v3 patch:
http://marc.info/?l=linux-kernel&m=139767371027557&w=2

jirka
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