Regarding the basic use of perf top command

From: ankurengg2003@gmail.com (ankur dwivedi)
To: kernelnewbies@lists.kernelnewbies.org
Subject: Regarding the basic use of perf top command
Date: Thu, 14 Jul 2011 12:32:45 +0530	[thread overview]
Message-ID: <CABW4kEc9uqODceV9LTfu-PqFHAAKfiOa9QWmAbSWZggkS9c8Pg@mail.gmail.com> (raw)
In-Reply-To: <4E1DBC53.40901@nyu.edu>

Hi,

The links provided gives description about the perf tool. As i mentioned
before, i was interested in the significance of the following:

1. irqs/sec
2. samples
3. pcnt

A brief explanation will suffice, as i am also looking into the code of perf
top.

Thanks
Ankur

On Wed, Jul 13, 2011 at 9:10 PM, Vipin <vj358@nyu.edu> wrote:

> **
> Hi,
>
> I think this should suffice
> https://perf.wiki.kernel.org/index.php/Tutorial#Live_analysis_with_perf_top
>
> Rest of the information is archived here
> http://lxr.linux.no/linux+v2.6.39/tools/perf/Documentation/
>
> The value of 1000Hz means the frequency at which the system's timer is
> programmed to interrupt the kernel. It is a kernel configurable option.
>
> Thanks
> Vipin
>
> On 07/13/2011 10:59 AM, ankur dwivedi wrote:
>
> Hi,
>
> My question is regarding the basic use of perf top command in linux.
>
> The following is the snap shot of running a "*perf top -e cache-misses*"
> command from console:
>
>
> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------
>    PerfTop:      76* irqs/sec*  kernel:14.5%  exact:  0.0% [1000Hz
> cache-misses],  (all, 12 CPUs)
>
> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>              *samples*  *pcnt* function                DSO
>              _______ _____ _______________________
> ____________________________________
>
>                48.00 36.9% get_page_from_freelist
> [kernel.kallsyms]
>                12.00  9.2% JS_CallTracer
> /usr/lib/xulrunner-1.9.2/libmozjs.so
>                12.00  9.2% JS_TraceChildren
> /usr/lib/xulrunner-1.9.2/libmozjs.so
>                 8.00  6.2% dso__find_symbol
> /usr/bin/perf
>                 7.00  5.4% native_flush_tlb_single
> [kernel.kallsyms]
>                 6.00  4.6% _int_malloc             /lib/libc-2.12.90.so
>
>
>
> What i want to know is the significance of different parameters here which
> are the following:
> 1. irqs/sec
> 2. samples
> 3. pcnt
>
> It also shows a value of 1000Hz. what is the meaning of that.
>
> I searched regarding these in the internet, but was unable to find a good
> explanation
>
> Thanks
> Ankur
>
>
>
> _______________________________________________
> Kernelnewbies mailing listKernelnewbies at kernelnewbies.orghttp://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
>

-- 
Thanks

Ankur Dwivedi
Cavium Networks Inc
Office Number - +1 650 623 3643
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