From: Arnd Bergmann <arnd@arndb•de>
To: linuxppc-dev@ozlabs•org
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom•com>,
Paul Mackerras <paulus@samba•org>
Subject: Re: [patch 05/18] PS3: Fix sparse warnings
Date: Wed, 6 Jun 2007 16:21:59 +0200 [thread overview]
Message-ID: <200706061621.59963.arnd@arndb.de> (raw)
In-Reply-To: <46662326.4030706@am.sony.com>
On Wednesday 06 June 2007, Geoff Levand wrote:
> -=A0=A0=A0=A0=A0=A0=A0spu->local_store =3D ioremap(spu->local_store_phys,=
LS_SIZE);
> +=A0=A0=A0=A0=A0=A0=A0spu->local_store =3D (__force void *)ioremap(spu->l=
ocal_store_phys,
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 =A0 L=
S_SIZE);
I haven't noticed this before, but it seems to be a preexisting bug:
You map the local_store as with the guarded page table bit set, which
causes a performance degradation when accessing the memory from kernel
space.
If you're lucky, your hypervisor knows this and will fix it up for
you, but I would replace the ioremap call with an
ioremap_flags(..., _PAGE_NO_CACHE); to be on the safe side.
If you want to measure the impact, I'd suggest timing a user space
read() on the mem file of a running SPU context.
Arnd <><
next prev parent reply other threads:[~2007-06-06 14:22 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20070606024407.786638029@am.sony.com>
2007-06-06 2:59 ` [patch 01/18] Cell: Add spu shutdown method Geoff Levand
2007-06-06 4:08 ` Michael Ellerman
2007-06-06 14:41 ` André Detsch
2007-06-06 2:59 ` [patch 02/18] PS3: Rename IPI symbols Geoff Levand
2007-06-06 3:11 ` Stephen Rothwell
2007-06-06 14:48 ` Will Schmidt
2007-06-06 20:47 ` Geoff Levand
2007-06-06 20:49 ` Geoff Levand
2007-06-06 2:59 ` [patch 03/18] PS3: Use __maybe_unused Geoff Levand
2007-06-06 4:05 ` Michael Ellerman
2007-06-06 22:37 ` Geoff Levand
2007-06-06 2:59 ` [patch 04/18] PS3: Compare firmware version Geoff Levand
2007-06-06 2:59 ` [patch 05/18] PS3: Fix sparse warnings Geoff Levand
2007-06-06 14:21 ` Arnd Bergmann [this message]
2007-06-07 14:34 ` Geoff Levand
2007-06-08 5:59 ` Takao Shinohara
2007-06-06 2:59 ` [patch 06/18] PS3: Add support for HDMI RGB Full Range mode Geoff Levand
2007-06-06 3:00 ` [patch 07/18] PS3: Make ps3av.h usable from user space Geoff Levand
2007-06-06 7:46 ` Christoph Hellwig
2007-06-06 11:27 ` Geert Uytterhoeven
2007-06-06 16:44 ` Geoff Levand
2007-06-07 19:15 ` Christoph Hellwig
2007-06-06 3:00 ` [patch 08/18] PS3: Kexec support Geoff Levand
2007-06-06 4:01 ` Michael Ellerman
2007-06-06 21:55 ` Geoff Levand
2007-06-07 1:25 ` Stephen Rothwell
2007-06-07 1:33 ` Geoff Levand
2007-06-07 2:48 ` Stephen Rothwell
2007-06-07 2:31 ` Michael Ellerman
2007-06-07 2:54 ` Benjamin Herrenschmidt
2007-06-10 0:13 ` Geoff Levand
2007-06-09 8:17 ` [patch 08/18] PS3: Kexec support (and a tutoral on the kexec flow for 64 bit powerpc) Milton Miller
2007-06-09 22:47 ` Geoff Levand
2007-06-06 3:00 ` [patch 09/18] PS3: System-bus rework Geoff Levand
2007-06-06 6:43 ` Geert Uytterhoeven
2007-06-11 7:07 ` Milton Miller
2007-06-11 15:39 ` Geoff Levand
2007-06-11 15:45 ` Geert Uytterhoeven
2007-06-06 3:00 ` [patch 10/18] PS3: System-bus uevent Geoff Levand
2007-06-06 3:00 ` [patch 11/18] PS3: System-bus modinfo attribute Geoff Levand
2007-06-06 3:17 ` Stephen Rothwell
2007-06-06 3:00 ` [patch 12/18] PS3: Repository probe cleanups Geoff Levand
2007-06-06 3:01 ` [patch 13/18] PS3: USB system-bus rework Geoff Levand
2007-06-06 3:01 ` [patch 14/18] PS3: Vuart rework Geoff Levand
2007-06-06 3:01 ` [patch 15/18] PS3: System manager re-work Geoff Levand
2007-06-06 6:51 ` Geert Uytterhoeven
2007-06-06 3:01 ` [patch 16/18] PS3: Rework AV settings driver Geoff Levand
2007-06-06 6:49 ` Geert Uytterhoeven
2007-06-06 3:01 ` [patch 17/18] PS3: Frame buffer system-bus rework Geoff Levand
2007-06-06 6:51 ` Geert Uytterhoeven
2007-06-06 15:56 ` [Linux-fbdev-devel] " Antonino A. Daplas
2007-06-06 23:08 ` Geoff Levand
2007-06-06 23:37 ` Antonino A. Daplas
2007-06-06 3:01 ` [patch 18/18] PS3: Device registration routines Geoff Levand
2007-06-06 6:57 ` Geert Uytterhoeven
2007-06-06 12:21 ` Geert Uytterhoeven
2007-06-06 3:04 ` [patch 13/18] PS3: USB system-bus rework Geoff Levand
2007-06-08 23:22 ` [patch] PS3: Fix USB return value Geoff Levand
2007-06-25 7:30 ` Greg KH
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