This is a note to let you know that I've just added the patch titled
perf/x86: Fix intel QPI uncore event definitions
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-x86-fix-intel-qpi-uncore-event-definitions.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c9601247f8f3fdc18aed7ed7e490e8dfcd07f122 Mon Sep 17 00:00:00 2001
From: Vince Weaver <vincent.weaver@xxxxxxxxx>
Date: Fri, 2 Aug 2013 10:47:34 -0400
Subject: perf/x86: Fix intel QPI uncore event definitions
From: Vince Weaver <vincent.weaver@xxxxxxxxx>
commit c9601247f8f3fdc18aed7ed7e490e8dfcd07f122 upstream.
John McCalpin reports that the "drs_data" and "ncb_data" QPI
uncore events are missing the "extra bit" and always return zero
values unless the bit is properly set.
More details from him:
According to the Xeon E5-2600 Product Family Uncore Performance
Monitoring Guide, Table 2-94, about 1/2 of the QPI Link Layer events
(including the ones that "perf" calls "drs_data" and "ncb_data") require
that the "extra bit" be set.
This was confusing for a while -- a note at the bottom of page 94 says
that the "extra bit" is bit 16 of the control register.
Unfortunately, Table 2-86 clearly says that bit 16 is reserved and must
be zero. Looking around a bit, I found that bit 21 appears to be the
correct "extra bit", and further investigation shows that "perf" actually
agrees with me:
[root@c560-003.stampede]# cat /sys/bus/event_source/devices/uncore_qpi_0/format/event
config:0-7,21
So the command
# perf -e "uncore_qpi_0/event=drs_data/"
Is the same as
# perf -e "uncore_qpi_0/event=0x02,umask=0x08/"
While it should be
# perf -e "uncore_qpi_0/event=0x102,umask=0x08/"
I confirmed that this last version gives results that agree with the
amount of data that I expected the STREAM benchmark to move across the QPI
link in the second (cross-chip) test of the original script.
Reported-by: John McCalpin <mccalpin@xxxxxxxxxxxxxxx>
Signed-off-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
Cc: zheng.z.yan@xxxxxxxxx
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1308021037280.26119@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event_intel_uncore.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
@@ -314,8 +314,8 @@ static struct uncore_event_desc snbep_un
static struct uncore_event_desc snbep_uncore_qpi_events[] = {
INTEL_UNCORE_EVENT_DESC(clockticks, "event=0x14"),
INTEL_UNCORE_EVENT_DESC(txl_flits_active, "event=0x00,umask=0x06"),
- INTEL_UNCORE_EVENT_DESC(drs_data, "event=0x02,umask=0x08"),
- INTEL_UNCORE_EVENT_DESC(ncb_data, "event=0x03,umask=0x04"),
+ INTEL_UNCORE_EVENT_DESC(drs_data, "event=0x102,umask=0x08"),
+ INTEL_UNCORE_EVENT_DESC(ncb_data, "event=0x103,umask=0x04"),
{ /* end: all zeroes */ },
};
Patches currently in stable-queue which might be from vincent.weaver@xxxxxxxxx are
queue-3.10/perf-arm-fix-armpmu_map_hw_event.patch
queue-3.10/perf-x86-fix-intel-qpi-uncore-event-definitions.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html