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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	alan@lxorguk.ukuu.org.uk, Andre Przywara <osp@andrep.de>,
	"H. Peter Anvin" <hpa@linux.intel.com>,
	CAI Qian <caiqian@redhat.com>
Subject: [ 26/27] x86, amd: Disable way access filter on Piledriver CPUs
Date: Thu,  6 Dec 2012 16:59:10 -0800	[thread overview]
Message-ID: <20121207005833.635875559@linuxfoundation.org> (raw)
In-Reply-To: <20121207005825.232489605@linuxfoundation.org>

3.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andre Przywara <andre.przywara@amd.com>

commit 2bbf0a1427c377350f001fbc6260995334739ad7 upstream.

The Way Access Filter in recent AMD CPUs may hurt the performance of
some workloads, caused by aliasing issues in the L1 cache.
This patch disables it on the affected CPUs.

The issue is similar to that one of last year:
http://lkml.indiana.edu/hypermail/linux/kernel/1107.3/00041.html
This new patch does not replace the old one, we just need another
quirk for newer CPUs.

The performance penalty without the patch depends on the
circumstances, but is a bit less than the last year's 3%.

The workloads affected would be those that access code from the same
physical page under different virtual addresses, so different
processes using the same libraries with ASLR or multiple instances of
PIE-binaries. The code needs to be accessed simultaneously from both
cores of the same compute unit.

More details can be found here:
http://developer.amd.com/Assets/SharedL1InstructionCacheonAMD15hCPU.pdf

CPUs affected are anything with the core known as Piledriver.
That includes the new parts of the AMD A-Series (aka Trinity) and the
just released new CPUs of the FX-Series (aka Vishera).
The model numbering is a bit odd here: FX CPUs have model 2,
A-Series has model 10h, with possible extensions to 1Fh. Hence the
range of model ids.

Signed-off-by: Andre Przywara <osp@andrep.de>
Link: http://lkml.kernel.org/r/1351700450-9277-1-git-send-email-osp@andrep.de
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/kernel/cpu/amd.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -631,6 +631,20 @@ static void __cpuinit init_amd(struct cp
 		}
 	}
 
+	/*
+	 * The way access filter has a performance penalty on some workloads.
+	 * Disable it on the affected CPUs.
+	 */
+	if ((c->x86 == 0x15) &&
+	    (c->x86_model >= 0x02) && (c->x86_model < 0x20)) {
+		u64 val;
+
+		if (!rdmsrl_safe(0xc0011021, &val) && !(val & 0x1E)) {
+			val |= 0x1E;
+			wrmsrl_safe(0xc0011021, val);
+		}
+	}
+
 	cpu_detect_cache_sizes(c);
 
 	/* Multi core CPU? */



  parent reply	other threads:[~2012-12-07  1:01 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-07  0:58 [ 00/27] 3.6.10-stable review Greg Kroah-Hartman
2012-12-07  0:58 ` [ 01/27] Dove: Attempt to fix PMU/RTC interrupts Greg Kroah-Hartman
2012-12-07  0:58 ` [ 02/27] Dove: Fix irq_to_pmu() Greg Kroah-Hartman
2012-12-07  0:58 ` [ 03/27] drm/radeon/dce4+: dont use radeon_crtc for vblank callback Greg Kroah-Hartman
2012-12-07  0:58 ` [ 04/27] drm/radeon: properly handle mc_stop/mc_resume on evergreen+ (v2) Greg Kroah-Hartman
2012-12-07  0:58 ` [ 05/27] drm/radeon: properly track the crtc not_enabled case evergreen_mc_stop() Greg Kroah-Hartman
2012-12-07  0:58 ` [ 06/27] mm/vmemmap: fix wrong use of virt_to_page Greg Kroah-Hartman
2012-12-07  0:58 ` [ 07/27] mm: vmscan: fix endless loop in kswapd balancing Greg Kroah-Hartman
2012-12-07  0:58 ` [ 08/27] mm: soft offline: split thp at the beginning of soft_offline_page() Greg Kroah-Hartman
2012-12-07  0:58 ` [ 09/27] target: Fix handling of aborted commands Greg Kroah-Hartman
2012-12-07  0:58 ` [ 10/27] iwlwifi: fix the basic CCK rates calculation Greg Kroah-Hartman
2012-12-07  0:58 ` [ 11/27] ARM: Kirkwood: Update PCI-E fixup Greg Kroah-Hartman
2012-12-07  0:58 ` [ 12/27] x86, fpu: Avoid FPU lazy restore after suspend Greg Kroah-Hartman
2012-12-07  0:58 ` [ 13/27] workqueue: exit rescuer_thread() as TASK_RUNNING Greg Kroah-Hartman
2012-12-07  0:58 ` [ 14/27] mac80211: fix remain-on-channel (non-)cancelling Greg Kroah-Hartman
2012-12-07  0:58 ` [ 15/27] md/raid1{,0}: fix deadlock in bitmap_unplug Greg Kroah-Hartman
2012-12-07  0:59 ` [ 16/27] i7300_edac: Fix error flag testing Greg Kroah-Hartman
2012-12-07  0:59 ` [ 17/27] Revert "sched, autogroup: Stop going ahead if autogroup is disabled" Greg Kroah-Hartman
2012-12-07 17:22   ` Joseph Salisbury
2012-12-07 17:30     ` Joseph Salisbury
2012-12-09 23:41       ` Ben Hutchings
2012-12-07 17:31     ` Greg Kroah-Hartman
2012-12-07 17:43       ` Joseph Salisbury
2012-12-07  0:59 ` [ 18/27] bnx2x: remove redundant warning log Greg Kroah-Hartman
2012-12-07  0:59 ` [ 19/27] i7core_edac: fix panic when accessing sysfs files Greg Kroah-Hartman
2012-12-07  0:59 ` [ 20/27] s390/mm: have 16 byte aligned struct pages Greg Kroah-Hartman
2012-12-07 10:00   ` Heiko Carstens
2012-12-07 15:07     ` Greg Kroah-Hartman
2012-12-07  0:59 ` [ 21/27] net: qmi_wwan: adding more ZTE devices Greg Kroah-Hartman
2012-12-07  0:59 ` [ 22/27] net: qmi_wwan: add Huawei E173 Greg Kroah-Hartman
2012-12-07  0:59 ` [ 23/27] ACPI: missing break Greg Kroah-Hartman
2012-12-07  0:59 ` [ 24/27] i915: Quirk no_lvds on Gigabyte GA-D525TUD ITX motherboard Greg Kroah-Hartman
2012-12-07  4:36   ` Calvin Walton
2012-12-07 16:37     ` Greg Kroah-Hartman
2012-12-07  0:59 ` [ 25/27] drm/i915: Add no-lvds quirk for Supermicro X7SPA-H Greg Kroah-Hartman
2012-12-07  0:59 ` Greg Kroah-Hartman [this message]
2012-12-07  0:59 ` [ 27/27] 8139cp: revert "set ring address before enabling receiver" Greg Kroah-Hartman
2012-12-07 13:36 ` [ 00/27] 3.6.10-stable review Holger Hoffstaette
2012-12-08  0:46 ` Shuah Khan
2012-12-08  0:58   ` Shuah Khan
2012-12-08  5:40 ` satoru takeuchi

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