* [RFC] i386-arch fixes/enhancements
@ 2003-03-07 3:08 J.A. Magallon
2003-03-07 3:11 ` J.A. Magallon
0 siblings, 1 reply; 3+ messages in thread
From: J.A. Magallon @ 2003-03-07 3:08 UTC (permalink / raw)
To: Lista Linux-Kernel; +Cc: Marcelo Tosatti
Hi all...
This is set of small patches that allow a finer tuning of i386 arch, and fix a
small bug:
- 20-x86-p4-prefetch: enables prefetch also for p4. This is a pending bug, IMHO.
- 21-x86-pII: splits Pentium-II as a separate config option; yes some of us
still have oldies and would like a slightly better optimized kernel
- 22-x86-check_gcc: use check_gcc also for Intel CPUs (like others already do)
to get better gcc flags.
- 23-x86-mb: implement memory barriers with specific instructions in p3 and p4
(credits go to Zwane Mwaikambo <zwane@linux.realnet.co.sz>)
Could this ever get into mainline ? Perhaps the only questionable piece is
the mb changes. How about next -pre ?
TIA
--
J.A. Magallon <jamagallon@able.es> \ Software is like sex:
werewolf.able.es \ It's better when it's free
Mandrake Linux release 9.1 (Cooker) for i586
Linux 2.4.21-pre4-jam1 (gcc 3.2.2 (Mandrake Linux 9.1 3.2.2-1mdk))
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RFC] i386-arch fixes/enhancements
2003-03-07 3:08 [RFC] i386-arch fixes/enhancements J.A. Magallon
@ 2003-03-07 3:11 ` J.A. Magallon
0 siblings, 0 replies; 3+ messages in thread
From: J.A. Magallon @ 2003-03-07 3:11 UTC (permalink / raw)
To: linux-kernel
[-- Attachment #1: Type: text/plain, Size: 1064 bytes --]
On 03.07 04:08, J.A. Magallon wrote:
> Hi all...
>
> This is set of small patches that allow a finer tuning of i386 arch, and fix a
> small bug:
>
> - 20-x86-p4-prefetch: enables prefetch also for p4. This is a pending bug, IMHO.
> - 21-x86-pII: splits Pentium-II as a separate config option; yes some of us
> still have oldies and would like a slightly better optimized kernel
> - 22-x86-check_gcc: use check_gcc also for Intel CPUs (like others already do)
> to get better gcc flags.
> - 23-x86-mb: implement memory barriers with specific instructions in p3 and p4
> (credits go to Zwane Mwaikambo <zwane@linux.realnet.co.sz>)
>
> Could this ever get into mainline ? Perhaps the only questionable piece is
> the mb changes. How about next -pre ?
>
Ooops. Here they go...
--
J.A. Magallon <jamagallon@able.es> \ Software is like sex:
werewolf.able.es \ It's better when it's free
Mandrake Linux release 9.1 (Cooker) for i586
Linux 2.4.21-pre4-jam1 (gcc 3.2.2 (Mandrake Linux 9.1 3.2.2-1mdk))
[-- Attachment #2: 20-x86-p4-prefetch.bz2 --]
[-- Type: application/x-bzip, Size: 360 bytes --]
[-- Attachment #3: 21-x86-pII.bz2 --]
[-- Type: application/x-bzip, Size: 818 bytes --]
[-- Attachment #4: 22-x86-check_gcc.bz2 --]
[-- Type: application/x-bzip, Size: 324 bytes --]
[-- Attachment #5: 23-x86-mb.bz2 --]
[-- Type: application/x-bzip, Size: 826 bytes --]
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RFC] i386-arch fixes/enhancements
@ 2003-03-07 11:12 Margit Schubert-While
0 siblings, 0 replies; 3+ messages in thread
From: Margit Schubert-While @ 2003-03-07 11:12 UTC (permalink / raw)
To: linux-kernel
Nice to see somebody is pushing this. I am getting fed up wtih
applying these to every 2.4.xx.
Note that with GCC >= 3.x(Not sure about "x", definitely 3.2), the P4
compile option correctly
generates add/sub instructions instead of the "P4 killer" inc/dec.
Of course, in include/asm-i386, we still have incs/decs in
processor.h, atomic.h, rwsem.h, semaphore.h uaccess.h, system.h,
string.h, spinlock.h and smplock.h.
With the patches and changing the includes, I can get a 5-10% improvement
with a hefty DB app on a UP P4 which isn't to be sneezed at.
And perhaps somebody should take a squint at the "copy_xxx_user".
IMHO, this really should be inlined.
Try running a DB app which bounces semaphores at a terrific rate and what
do you see at the top of readprofile ? Yep, you guessed it.
Margit
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2003-03-07 11:12 Margit Schubert-While
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