Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761583AbYCZAmp (ORCPT ); Tue, 25 Mar 2008 20:42:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757163AbYCZAmh (ORCPT ); Tue, 25 Mar 2008 20:42:37 -0400 Received: from mga03.intel.com ([143.182.124.21]:1044 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754334AbYCZAmg (ORCPT ); Tue, 25 Mar 2008 20:42:36 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.25,555,1199692800"; d="scan'208";a="223188276" Date: Tue, 25 Mar 2008 17:39:12 -0700 From: Suresh Siddha To: Andrew Morton Cc: "Siddha, Suresh B" , Ingo Molnar , Thomas Gleixner , bugme-daemon@bugzilla.kernel.org, linux-kernel@vger.kernel.org, "Rafael J. Wysocki" , venkatesh.pallipadi@intel.com, arjan@linux.intel.com, bug-track@fisher-privat.net Subject: Re: [Bug 10328] New: [regression] performance drop for glx Message-ID: <20080326003912.GB3313@linux-os.sc.intel.com> References: <20080325152809.e2b07251.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080325152809.e2b07251.akpm@linux-foundation.org> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4267 Lines: 105 On Tue, Mar 25, 2008 at 03:28:09PM -0700, Andrew Morton wrote: > (switched to email. Please respond via emailed reply-to-all, not via the > bugzilla web interface). > > On Tue, 25 Mar 2008 15:11:15 -0700 (PDT) > bugme-daemon@bugzilla.kernel.org wrote: > > > http://bugzilla.kernel.org/show_bug.cgi?id=10328 > > > > Summary: [regression] performance drop for glx > > > > after commit 4138cc3418f5eaa7524ff8e927102863f1ba0ea5 i expirience some grafik > > related perfomance issues. > > > > I used glxgears for test. > > before this patch: 1281.005 FPS > > and after: 765.000 FPS > > It nearly halved. > > > latest tested commit a4083c9271e0a697278e089f2c0b9a95363ada0a > > still hase bad performance. > > > > I use Pentium D with 2GB RAM, Grafick: i945G, ICH7 > > > > That's > > : commit 4138cc3418f5eaa7524ff8e927102863f1ba0ea5 > : Author: Siddha, Suresh B > : Date: Wed Jan 30 13:33:43 2008 +0100 > : > : x86: set strong uncacheable where UC is really desired > : > : Also use _PAGE_PWT for all the mappings which need uncache mapping. > : Instead of existing PAT2 which is UC- (and can be overwritten by MTRRs), > : we now use PAT3 which is strong uncacheable. > : > : This makes it consistent with pgprot_noncached() Alexey, Can you please try the appended patch? Andrew, can you please push the appended patch for 2.6.25? Thanks. --- fb drivers are using ioremap()/ioremap_nocache(), followed by mtrr_add with WC attribute. Recent changes in page attribute code made both ioremap()/ioremap_nocache() mappings as UC (instead of previous UC-). This breaks the graphics performance, as the effective memory type is UC instead of expected WC. The correct way to fix this is to add ioremap_wc() (which uses UC- in the absence of PAT kernel support and WC with PAT) and change all the fb drivers to use this new ioremap_wc() API. We can take this correct and longer route for post 2.6.25. For now, revert back to the UC- behavior for ioremap/ioremap_nocache. Signed-off-by: Suresh Siddha Signed-off-by: Venkatesh Pallipadi Cc: Arjan van de Ven --- diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 4afaba0..794895c 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -137,7 +137,11 @@ static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size, switch (mode) { case IOR_MODE_UNCACHED: default: - prot = PAGE_KERNEL_NOCACHE; + /* + * FIXME: we will use UC MINUS for now, as video fb drivers + * depend on it. Upcoming ioremap_wc() will fix this behavior. + */ + prot = PAGE_KERNEL_UC_MINUS; break; case IOR_MODE_CACHED: prot = PAGE_KERNEL; diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h index 174b877..9cf472a 100644 --- a/include/asm-x86/pgtable.h +++ b/include/asm-x86/pgtable.h @@ -85,6 +85,7 @@ extern pteval_t __PAGE_KERNEL, __PAGE_KERNEL_EXEC; #define __PAGE_KERNEL_RX (__PAGE_KERNEL_EXEC & ~_PAGE_RW) #define __PAGE_KERNEL_EXEC_NOCACHE (__PAGE_KERNEL_EXEC | _PAGE_PCD | _PAGE_PWT) #define __PAGE_KERNEL_NOCACHE (__PAGE_KERNEL | _PAGE_PCD | _PAGE_PWT) +#define __PAGE_KERNEL_UC_MINUS (__PAGE_KERNEL | _PAGE_PCD) #define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RX | _PAGE_USER) #define __PAGE_KERNEL_VSYSCALL_NOCACHE (__PAGE_KERNEL_VSYSCALL | _PAGE_PCD | _PAGE_PWT) #define __PAGE_KERNEL_LARGE (__PAGE_KERNEL | _PAGE_PSE) @@ -101,6 +102,7 @@ extern pteval_t __PAGE_KERNEL, __PAGE_KERNEL_EXEC; #define PAGE_KERNEL_EXEC MAKE_GLOBAL(__PAGE_KERNEL_EXEC) #define PAGE_KERNEL_RX MAKE_GLOBAL(__PAGE_KERNEL_RX) #define PAGE_KERNEL_NOCACHE MAKE_GLOBAL(__PAGE_KERNEL_NOCACHE) +#define PAGE_KERNEL_UC_MINUS MAKE_GLOBAL(__PAGE_KERNEL_UC_MINUS) #define PAGE_KERNEL_EXEC_NOCACHE MAKE_GLOBAL(__PAGE_KERNEL_EXEC_NOCACHE) #define PAGE_KERNEL_LARGE MAKE_GLOBAL(__PAGE_KERNEL_LARGE) #define PAGE_KERNEL_LARGE_EXEC MAKE_GLOBAL(__PAGE_KERNEL_LARGE_EXEC) -- 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/