RE: Kernel 2.6.3 patch for Intel Compiler 8.0

RE: Kernel 2.6.3 patch for Intel Compiler 8.0

[Nakajima, Jun]

In 2.6, we already have sufficient changes for Intel IPF Compiler to
build the kernel, especially intrinscs changes, and you should not need
a patch. To make it faster, we might want to use PGO (profile guided
optimization) provided by the compiler; yes, it's available even for the
kernel with a driver.

Thanks,
Jun

>-----Original Message-----
>From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-
>owner@vger.kernel.org] On Behalf Of Norihiko Mukouyama
>Sent: Tuesday, March 09, 2004 6:08 PM
>To: Stefan Smietanowski; Norberto Bensa
>Cc: Ingo at Pyrillion; linux-kernel@vger.kernel.org
>Subject: RE: Kernel 2.6.3 patch for Intel Compiler 8.0
>
>Hi,Stefan!!
>
>>1/3 of the things are faster with icc. 2/3 of the things are faster
>>with gcc. Performance numbers not given.
>
>Thank you very much.
>I understood that meaning.
>
>By the way,
>
>I would like to learn the result of making his patch run on Itanium2.
>Because, the difference of the performance of the compiler being sure
to
>influence most
>remarkably.
>
>Can  anyone try?
>
>Thanks.
>
>Norihiko
>
>
>-
>To unsubscribe from this list: send the line "unsubscribe linux-kernel"
in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>Please read the FAQ at  http://www.tux.org/lkml/

AW: Kernel 2.6.3 patch for Intel Compiler 8.0

[Ingo at Pyrillion]

Hi Jun,

the patch I submitted is for icc 8.0, i.e. I386 platform only.

Did I understand your last message right that you even do not
need a kernel patch for icc, i.e. I386?

If so, then try to compile the 2.6.3 kernel using icc without
applying my patch and see what happens if icc "tries" to compile
hybrid code, i.e. mixed assembly and C statements....
The current icc 8.0 (and also icc 7.0) makes FATAL mistakes
compiling those mixings. Just check the object file that results
from "dec_and_lock.c" in arch/i386/lib using a disassembler.

Rgs, Ingo.

-----Ursprüngliche Nachricht-----
Von: Nakajima, Jun [mailto:jun.nakajima@intel.com] 
Gesendet: Mittwoch, 10. März 2004 03:53
An: Norihiko Mukouyama; Stefan Smietanowski; Norberto Bensa
Cc: Ingo at Pyrillion; linux-kernel@vger.kernel.org
Betreff: RE: Kernel 2.6.3 patch for Intel Compiler 8.0


In 2.6, we already have sufficient changes for Intel IPF Compiler to
build the kernel, especially intrinscs changes, and you should not need
a patch. To make it faster, we might want to use PGO (profile guided
optimization) provided by the compiler; yes, it's available even for the
kernel with a driver.

Thanks,
Jun

>-----Original Message-----
>From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel- 
>owner@vger.kernel.org] On Behalf Of Norihiko Mukouyama
>Sent: Tuesday, March 09, 2004 6:08 PM
>To: Stefan Smietanowski; Norberto Bensa
>Cc: Ingo at Pyrillion; linux-kernel@vger.kernel.org
>Subject: RE: Kernel 2.6.3 patch for Intel Compiler 8.0
>
>Hi,Stefan!!
>
>>1/3 of the things are faster with icc. 2/3 of the things are faster 
>>with gcc. Performance numbers not given.
>
>Thank you very much.
>I understood that meaning.
>
>By the way,
>
>I would like to learn the result of making his patch run on Itanium2. 
>Because, the difference of the performance of the compiler being sure
to
>influence most
>remarkably.
>
>Can  anyone try?
>
>Thanks.
>
>Norihiko
>
>
>-
>To unsubscribe from this list: send the line "unsubscribe linux-kernel"
in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>Please read the FAQ at  http://www.tux.org/lkml/

RE: Kernel 2.6.3 patch for Intel Compiler 8.0

[Norihiko Mukouyama]

Hi All!!

>I used the patch to compile two identical kernels with gcc 3.3.3 and
>icc 8.0 with oprofile support built in.
>The optimization switches were chosen quite conservative, i.e.
>"-O2 -Ob1", no IPO, and of course: no MMX, SSE, and SSE2 stuff inside
>the kernel (thus disabling Intel's great vectorizer).
>Profiling: lmbench ran ten times but time measurements were taken from
>oprofile (on Pentium 4, GLOBAL_POWER_EVENTS in kernel space only, 
>counter overflow: 3.000).
>Results: 33% of the lmbench procs faster on icc, 66% faster on gcc.

Really???

If it is ture using icc 66% faster than gcc., It is wonderful. 
Could you show us detail data to  lmbench results.

Thanks!!

Norihiko

AW: Kernel 2.6.3 patch for Intel Compiler 8.0

[Ingo at Pyrillion]

Hi again,

please read my last mail carefully: 
"33% procs faster on icc, 66% faster on gcc"
means that gcc (GNU) is superior. But the patch is a preliminary 
version...

greetings, Ingo.

-----Ursprüngliche Nachricht-----
Von: Norihiko Mukouyama [mailto:norihiko_m@jp.fujitsu.com] 
Gesendet: Mittwoch, 10. März 2004 01:50
An: Ingo at Pyrillion; 'Norberto Bensa'
Cc: linux-kernel@vger.kernel.org
Betreff: RE: Kernel 2.6.3 patch for Intel Compiler 8.0


Hi All!!

>I used the patch to compile two identical kernels with gcc 3.3.3 and 
>icc 8.0 with oprofile support built in. The optimization switches were 
>chosen quite conservative, i.e. "-O2 -Ob1", no IPO, and of course: no 
>MMX, SSE, and SSE2 stuff inside the kernel (thus disabling Intel's 
>great vectorizer).
>Profiling: lmbench ran ten times but time measurements were taken from 
>oprofile (on Pentium 4, GLOBAL_POWER_EVENTS in kernel space only, 
>counter overflow: 3.000).
>Results: 33% of the lmbench procs faster on icc, 66% faster on gcc.

Really???

If it is ture using icc 66% faster than gcc., It is wonderful. 
Could you show us detail data to  lmbench results.

Thanks!!

Norihiko

Re: Kernel 2.6.3 patch for Intel Compiler 8.0

[Norberto Bensa]

Ingo at Pyrillion wrote:
> patch to compile the kernel with Intel Compiler 8.0
> for Linux.

Speed improvements over same kernel compiled with gcc?

Thanks,
Norberto

AW: Kernel 2.6.3 patch for Intel Compiler 8.0

[Ingo at Pyrillion]

I used the patch to compile two identical kernels with gcc 3.3.3 and
icc 8.0 with oprofile support built in.
The optimization switches were chosen quite conservative, i.e.
"-O2 -Ob1", no IPO, and of course: no MMX, SSE, and SSE2 stuff inside
the kernel (thus disabling Intel's great vectorizer).
Profiling: lmbench ran ten times but time measurements were taken from
oprofile (on Pentium 4, GLOBAL_POWER_EVENTS in kernel space only, 
counter overflow: 3.000).
Results: 33% of the lmbench procs faster on icc, 66% faster on gcc.

Thus, take the kernel patch as a good basis for modifying the 
compiler switches and other things to get more performance gains. As
I know, a lot of people are looking for a patch.

Please check the patch file; you have to modify a lot of things in 2.6.3
to create a quite stable working version of the kernel. The patch is not
just about changing some minor Makefile things...

Kind rgs., Ingo.

-----Ursprüngliche Nachricht-----
Von: Norberto Bensa [mailto:norberto+linux-kernel@bensa.ath.cx] 
Gesendet: Mittwoch, 10. März 2004 01:09
An: Ingo at Pyrillion
Cc: linux-kernel@vger.kernel.org
Betreff: Re: Kernel 2.6.3 patch for Intel Compiler 8.0


Ingo at Pyrillion wrote:
> patch to compile the kernel with Intel Compiler 8.0
> for Linux.

Speed improvements over same kernel compiled with gcc?

Thanks,
Norberto