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Message-ID: <4b556b3292c18d793ff19e4f129200138045e4a6.camel@kernel.org>
Date: Thu, 01 Sep 2022 15:59:28 -0500
From: Tom Zanussi <zanussi@...nel.org>
To: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 0/5] tracing/hist: Add percentage histogram suffixes
On Thu, 2022-09-01 at 08:02 +0900, Masami Hiramatsu wrote:
> On Wed, 31 Aug 2022 16:35:25 -0500
> Tom Zanussi <zanussi@...nel.org> wrote:
>
> > Hi Masami,
> >
> > On Sat, 2022-08-27 at 13:03 +0900, Masami Hiramatsu (Google) wrote:
> > > Hi,
> > >
> > > Here is the 4th version of .percent and .graph suffixes for
> > > histogram
> > > trigger to show the value in percentage and in bar-graph
> > > respectively.
> > >
> > > I've rebased on Tom's hitcount patch[1/5] on the series and added
> > > a
> > > patch
> > > for supressing display of hitcount[5/5] in this version.
> >
> > This is a very nice patchset overall - the only question I have
> > concerns patch 5 for suppressing the hitcount. I actually think
> > the
> > patch is fine and does what it says nicely (and probably should
> > have
> > been done that way to begin with) but it looks like it would cause
> > problems for anyone already doing postprocessing and whose scripts
> > would be expecting the hitcount to be there. So changing the
> > default
> > behavior would require their scripts to change, and also now that I
> > look at it, the example output in Documentation/ as well.
>
> Good catch! Yeah, this type of change will need to update the docs.
> I missed that.
>
> >
> > How about adding an option like 'nohitcount' and having that patch
> > do
> > what it does but only if that option is set?
>
> Agreed. So something like this?
>
> echo hist:keys=pid:vals=runtime.graph:nohitcount (or NOHC for short)
>
> Maybe we can also add an option under <tracefs/>options/
Yeah, makes sense to me.
Thanks,
Tom
>
> >
> > Anyway, for the other ones, patches 2-4,
> >
> > Signed-off-by: Tom Zanussi <zanussi@...nel.org>
> > Tested-by: Tom Zanussi <zanussi@...nel.org
>
> Thank you!
>
> >
> > Thanks!
> >
> > Tom
> >
> > >
> > > This will help us to check the trend of the histogram instantly
> > > without any post processing tool.
> > >
> > > Here shows an example of the percentage and the bar graph of
> > > the hitcount of the running tasks.
> > >
> > > # cd /sys/kernel/debug/tracing/
> > > # echo
> > > hist:keys=pid:vals=hitcount.percent,hitcount.graph:sort=pid
> > > > \
> > > events/sched/sched_stat_runtime/trigger
> > > # sleep 10
> > > # cat events/sched/sched_stat_runtime/hist
> > > # event histogram
> > > #
> > > # trigger info:
> > > hist:keys=pid:vals=hitcount.percent,hitcount.graph:sort=pid:size=
> > > 2048
> > > [active]
> > > #
> > >
> > > { pid: 14 } hitcount (%): 4.68 hitcount:
> > > ###
> > > { pid: 16 } hitcount (%): 17.18 hitcount:
> > > ###########
> > > { pid: 57 } hitcount (%): 7.81 hitcount:
> > > #####
> > > { pid: 61 } hitcount (%): 31.25 hitcount:
> > > ####################
> > > { pid: 70 } hitcount (%): 4.68 hitcount:
> > > ###
> > > { pid: 77 } hitcount (%): 1.56 hitcount:
> > > #
> > > { pid: 145 } hitcount (%): 18.75 hitcount:
> > > ############
> > > { pid: 151 } hitcount (%): 9.37 hitcount:
> > > ######
> > > { pid: 152 } hitcount (%): 4.68 hitcount:
> > > ###
> > >
> > > Totals:
> > > Hits: 64
> > > Entries: 9
> > > Dropped: 0
> > >
> > > Of course if you explicitly specify the hitcount, it can show the
> > > hitcount as below;
> > >
> > > # cd /sys/kernel/debug/tracing/
> > > # echo hist:keys=pid:vals=hitcount,runtime:sort=pid > \
> > > events/sched/sched_stat_runtime/trigger
> > > # sleep 10
> > > # cat events/sched/sched_stat_runtime/hist
> > > # event histogram
> > > #
> > > # trigger info:
> > > hist:keys=pid:vals=hitcount,runtime:sort=pid:size=2048 [active]
> > > #
> > >
> > > { pid: 14 } hitcount: 2 runtime: 304876
> > > { pid: 16 } hitcount: 8 runtime: 300574
> > > { pid: 26 } hitcount: 2 runtime: 15578
> > > { pid: 32 } hitcount: 2 runtime: 219186
> > > { pid: 57 } hitcount: 3 runtime: 506003
> > > { pid: 61 } hitcount: 20 runtime: 1681473
> > > { pid: 69 } hitcount: 3 runtime: 201785
> > > { pid: 70 } hitcount: 4 runtime: 360608
> > > { pid: 77 } hitcount: 8 runtime: 4146935
> > > { pid: 145 } hitcount: 13 runtime: 7537994
> > > { pid: 155 } hitcount: 4 runtime: 2511937
> > > { pid: 156 } hitcount: 2 runtime: 1398886
> > >
> > > Totals:
> > > Hits: 71
> > > Entries: 12
> > > Dropped: 0
> > >
> > >
> > > Thank you,
> > >
> > > ---
> > >
> > > Masami Hiramatsu (Google) (4):
> > > tracing: Fix to check event_mutex is held while accessing
> > > trigger list
> > > tracing: Add .percent suffix option to histogram values
> > > tracing: Add .graph suffix option to histogram value
> > > tracing: Show hitcount value only when specified
> > >
> > > Tom Zanussi (1):
> > > tracing: Allow multiple hitcount values in histograms
> > >
> > >
> > > kernel/trace/trace.c | 3 -
> > > kernel/trace/trace_events_hist.c | 176
> > > ++++++++++++++++++++++++++++++-----
> > > kernel/trace/trace_events_trigger.c | 3 -
> > > 3 files changed, 156 insertions(+), 26 deletions(-)
> > >
> > > --
> > > Masami Hiramatsu (Google) <mhiramat@...nel.org>
> >
>
>
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