Re: kernel profiling

Re: kernel profiling

[Dimitris Michailidis]

Robert Walsh <rjwalsh@durables.org> writes:

> Other than /dev/profile, is there any mechanism available for
> profiling the kernel?  For example, has anyone implemented a
> __mcount() function to handle a kernel compiled with -pg, or is this
> even possible?
> 
> We're currently profiling the kernel NFS daemon (the entire path from
> network to disk) using SPECsfs and other benchmarking mechanisms, and
> before I start working on a home-grown profiling mechanism I'd like to
> make sure I'm not reinventing the wheel.
> 
> BTW: /proc/profile hasn't got enough granularity for our purposes and
> doesn't provide info such as call-graph statistics.

Back in May I posted a patch to enable kernel profiling using gprof, which
should give you the call graph statistics you want.  The patch basically
implements mcount() to collect statistics, adds a couple of files to /proc to 
make the statistics available to the user land, and provides a command,
kernprof, to generate gmon.out for consumption by gprof.  kernprof, in
addition to preparing data for gprof, also does the job of readprofile, with
a number of bugs of the latter fixed.

You can get the patch from

http://linuxwww.db.erau.edu/mail_archives/linux-kernel/May_99/2383.html

or other archives.  Since there has been no response to this patch there has
been no further development since the initial release, but it probably still
applies cleanly against the 2.2.x kernels.

As noted in the initial post, due to bugs in gcc/egcs that cause
miscompilation of programs that use -pg and regparms, to use this patch you
either need a hacked version of egcs or you need to disable the FASTCALLs in
the kernel (the latter is done in the IKD patch).

Let me know if you have any suggestions to improve the patch or need other
assistance.

-- 
Dimitris Michailidis                    dimitris@engr.sgi.com

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Re: kernel profiling

[Karim Yaghmour]

On Thu, 8 Jul 1999, Robert Walsh wrote:

> We're currently profiling the kernel NFS daemon (the entire path from
> network to disk) using SPECsfs and other benchmarking mechanisms, and
> before I start working on a home-grown profiling mechanism I'd like to
> make sure I'm not reinventing the wheel.

You might want to check on the tool i've been working on, which enables
you to see exactly what if happening on your system at all times. It
would enable you to see what time is spent in kernel, what time is
spent in the rest of the system, and why.

Moreover, the mechanisms I use are easily extendable. Therefore, if
you find the information given insufficient, you can make the kernel
generate more information without modifying too many things.

You can find the Linux 
Trace Toolkit at the following address :

http://www.info.polymtl.ca/users/karym/www/trace/

The information on how to use it is there and so is some information
on how it works. If you need more info, don't hesitate to contact me
if you need more information.

Of course, it's all under GPL ...

Regards.

==============================================
              Karim Yaghmour
          karym@info.polymtl.ca
            Computer Engineer
      Ecole Polytechnique de Montreal
==============================================

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Kernel profiling

[Steffen Persvold]

List readers,

Is it possible to use the kernel profiling functionality to do profiling on loadable modules ? If
no, is there any other easy method ?

Regards,
-- 
  Steffen Persvold   | Scalable Linux Systems |   Try out the world's best
 mailto:sp@scali.com |  http://www.scali.com  | performing MPI implementation:
Tel: (+47) 2262 8950 |   Olaf Helsets vei 6   |      - ScaMPI 1.13.8 -
Fax: (+47) 2262 8951 |   N0621 Oslo, NORWAY   | >320MBytes/s and <4uS latency

Re: Kernel profiling

[John Levon]

On Tue, Mar 12, 2002 at 08:29:22PM +0100, Steffen Persvold wrote:

> Is it possible to use the kernel profiling functionality to do
> profiling on loadable modules ?

I imagine it wouldn't be too hard to extend the profiling buffer for
the module text regions ...

> If no, is there any other easy method ?

http://oprofile.sf.net

regards
john

-- 
I am a complete moron for forgetting about endianness. May I be
forever marked as such.

Re: Kernel profiling

[Andi Kleen]

Steffen Persvold <sp@scali.com> writes:

> List readers,
> 
> Is it possible to use the kernel profiling functionality to do profiling on loadable modules ? If
> no, is there any other easy method ?

Either compile the module in or use oprofile (http://oprofile.sourceforge.net)
The later is better, because it is a much more powerful profiler than 
the builtin one. 

-Andi

kernel profiling

[Hui_Ning]

hi,

I am trying to do kernel profile using kernprof with the patch provided by
SGI on 2.4.18. I can't find the 2.95.3 gcc patch that must be used to
compile the kernel( the info on sgi's web site somehow is broken).  Does
anybody know where the patch is ? or any alternative I can use, like
a more stable gcc version without the need for a patch?

thanks for your help

hui

Re: kernel profiling

[Hanna Linder]

--On Tuesday, January 21, 2003 06:34:34 PM -0600 Hui_Ning@3com.com wrote:
> 
> hi,
> 
> I am trying to do kernel profile using kernprof with the patch provided by
> SGI on 2.4.18. I can't find the 2.95.3 gcc patch that must be used to
> compile the kernel( the info on sgi's web site somehow is broken).  Does
> anybody know where the patch is ? or any alternative I can use, like
> a more stable gcc version without the need for a patch?

Hello,

	I found that the default red hat 7.3 compiler (gcc-2.96-110)
did not need the patch and ran kernprof fine. 

Hanna

kernel profiling

[Yours Lovingly]

hello, 
i m trying to use kernel profiling to optimize nfs
cache performance in 2.4.18. But unfortunately i m
unable to access sgi's ftp site hosting kernprof.
But more unfortunately :
i turned on profiling on the kernel command line with
profile=2
but whenever i give a readprofile command, all i get
is a single line that goes like:
     0 total                 0.0000

1. please suggest a way to make readprofile work.
2. please suggest someother profiling mechanism that
could be of more help

thanks a lot

abhishek

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kernel profiling

[Yours Lovingly]

hello, 
i m trying to use kernel profiling to study nfs client
cache performance in 2.4.18.
But unfortunately :
i turned on profiling on the kernel command line with
profile=2
but whenever i give a readprofile command, all i get
is a single line that goes like:
     0 total                 0.0000

1. please suggest a way to make readprofile work.
2. please suggest someother profiling mechanism that
could be of more help

thanks a lot

abhishek

________________________________________________________________________
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       visit http://in.tv.yahoo.com

KERNEL PROFILING

[shesha bhushan]

HI ALL,
  I am trying to profile the linux kernel. Can any one suggest an easy way 
to do. Like, I wanted to see how much TCP is using CPU, how much of CPU is 
used in memcpy, etc.
Can any one please suggest me.

Thanking You
Shesha

_________________________________________________________________
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Re: KERNEL PROFILING

[Randy.Dunlap]

On Tue, 08 Apr 2003 07:58:54 +0000 "shesha bhushan" <bhushan_vadulas@hotmail.com> wrote:

| HI ALL,
|   I am trying to profile the linux kernel. Can any one suggest an easy way 
| to do. Like, I wanted to see how much TCP is using CPU, how much of CPU is 
| used in memcpy, etc.
| Can any one please suggest me.

Start with the file linux/Documentation/basic_profiling.txt
(it's in Linux 2.5.66-or-so or later).

It explains how to use oprofile and readprofile.

You can read about oprofile at http://oprofile.sourceforge.net/ .

You can read about basic in-kernel profiling using /proc/profile
and readprofile via 'man readprofile'.  It's simple to use.

--
~Randy

Re: KERNEL PROFILING

[shesha bhushan]

Hi
If I use the command line option "profile=2" while booting the system, why 
/proc/profile file is not created? Should I have to create it manually?

Thanking You'
Shesha





>From: "Randy.Dunlap" <rddunlap@osdl.org>
>To: "shesha bhushan" <bhushan_vadulas@hotmail.com>
>CC: linux-kernel@vger.kernel.org, kernelnewbies@nl.linux.org
>Subject: Re: KERNEL PROFILING
>Date: Tue, 8 Apr 2003 08:01:55 -0700
>
>On Tue, 08 Apr 2003 07:58:54 +0000 "shesha bhushan" 
><bhushan_vadulas@hotmail.com> wrote:
>
>| HI ALL,
>|   I am trying to profile the linux kernel. Can any one suggest an easy 
>way
>| to do. Like, I wanted to see how much TCP is using CPU, how much of CPU 
>is
>| used in memcpy, etc.
>| Can any one please suggest me.
>
>Start with the file linux/Documentation/basic_profiling.txt
>(it's in Linux 2.5.66-or-so or later).
>
>It explains how to use oprofile and readprofile.
>
>You can read about oprofile at http://oprofile.sourceforge.net/ .
>
>You can read about basic in-kernel profiling using /proc/profile
>and readprofile via 'man readprofile'.  It's simple to use.
>
>--
>~Randy


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Re: KERNEL PROFILING

[Randy.Dunlap]

I don't know why it's not created.

What kernel version is this?  Did you build the kernel
or is it from someone else who could have modified it?

The only failure that I see in profile setup/init is Out of Memory
if the profile buffer cannot be allocated.  Did you search thru
the boot message log for any errors?

~Randy


On Tue, 08 Apr 2003 19:42:03 +0000 "shesha bhushan" <bhushan_vadulas@hotmail.com> wrote:

| 
| Hi
| If I use the command line option "profile=2" while booting the system, why 
| /proc/profile file is not created? Should I have to create it manually?
| 
| Thanking You'
| Shesha
| 
| 
| 
| 
| 
| >From: "Randy.Dunlap" <rddunlap@osdl.org>
| >To: "shesha bhushan" <bhushan_vadulas@hotmail.com>
| >CC: linux-kernel@vger.kernel.org, kernelnewbies@nl.linux.org
| >Subject: Re: KERNEL PROFILING
| >Date: Tue, 8 Apr 2003 08:01:55 -0700
| >
| >On Tue, 08 Apr 2003 07:58:54 +0000 "shesha bhushan" 
| ><bhushan_vadulas@hotmail.com> wrote:
| >
| >| HI ALL,
| >|   I am trying to profile the linux kernel. Can any one suggest an easy 
| >way
| >| to do. Like, I wanted to see how much TCP is using CPU, how much of CPU 
| >is
| >| used in memcpy, etc.
| >| Can any one please suggest me.
| >
| >Start with the file linux/Documentation/basic_profiling.txt
| >(it's in Linux 2.5.66-or-so or later).
| >
| >It explains how to use oprofile and readprofile.
| >
| >You can read about oprofile at http://oprofile.sourceforge.net/ .
| >
| >You can read about basic in-kernel profiling using /proc/profile
| >and readprofile via 'man readprofile'.  It's simple to use.
| >
| >--
| >~Randy

Re: KERNEL PROFILING

[Andy Pfiffer]

> | 
> | Hi
> | If I use the command line option "profile=2" while booting the system, why 
> | /proc/profile file is not created? Should I have to create it manually?
> | 
> | Thanking You'
> | Shesha

You might want to double check your kernel command line after the system
has booted with "cat /proc/cmdline" and look for the "profile=2"
parameter.

% cat /proc/cmdline 
auto BOOT_IMAGE=linux-2.5.67 ro root=805 console=ttyS0,9600n8 profile=2
%