linux-kernel - Re: [RFCv2 00/48] perf tools: Add threads to record command

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Date:   Fri, 14 Sep 2018 12:37:41 +0300
From:   Alexey Budankov <alexey.budankov@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Jiri Olsa <jolsa@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Andi Kleen <andi@...stfloor.org>
Subject: Re: [RFCv2 00/48] perf tools: Add threads to record command

On 14.09.2018 11:28, Jiri Olsa wrote:
> On Fri, Sep 14, 2018 at 10:26:53AM +0200, Jiri Olsa wrote:
> 
> SNIP
> 
>>>> The threaded monitoring currently can't monitor backward maps
>>>> and there are probably more limitations which I haven't spotted
>>>> yet.
>>>>
>>>> So far I tested on laptop:
>>>>   http://people.redhat.com/~jolsa/record_threads/test-4CPU.txt
>>>>
>>>> and a one bigger server:
>>>>   http://people.redhat.com/~jolsa/record_threads/test-208CPU.txt
>>>>
>>>> I can see decrease in recorded LOST events, but both the benchmark
>>>> and the monitoring must be carefully configured wrt:
>>>>   - number of events (frequency)
>>>>   - size of the memory maps
>>>>   - size of events (callchains)
>>>>   - final perf.data size
>>>>
>>>> It's also available in:
>>>>   git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
>>>>   perf/record_threads
>>>>
>>>> thoughts? ;-) thanks
>>>> jirka
>>>
>>> It is preferable to split into smaller pieces that bring 
>>> some improvement proved by metrics numbers and ready for 
>>> merging and upstream. Do we have more metrics than the 
>>> data loss from trace AIO patches?
>>
>> well the primary focus is to get more events in,
>> so the LOST metric is the main one
> 
> actualy I was hoping, could you please run it through the same
> tests as you do for AIO code on some huge server? 

Yeah, I will, but it takes some time.

> 
> thanks,
> jirka
>