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FAILED: patch "[PATCH] perf/amd/uncore: Replace manual sampling check with" failed to apply to 4.19-stable tree

PATCH [email protected] 2 participants 2 messages Mar 16, 2020 – Mar 18, 2020

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Stable branch x86 perf events
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#0 lore raw

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f967140dfb7442e2db0868b03b961f9c59418a1b Mon Sep 17 00:00:00 2001
From: Kim Phillips <[email protected]>
Date: Wed, 11 Mar 2020 14:13:21 -0500
Subject: [PATCH] perf/amd/uncore: Replace manual sampling check with
CAP_NO_INTERRUPT flag

Enable the sampling check in kernel/events/core.c::perf_event_open(), which returns the more appropriate -EOPNOTSUPP.

BEFORE:

  $ sudo perf record -a -e instructions,l3_request_g1.caching_l3_cache_accesses true
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (l3_request_g1.caching_l3_cache_accesses).
  /bin/dmesg | grep -i perf may provide additional information.

With nothing relevant in dmesg.

AFTER:

  $ sudo perf record -a -e instructions,l3_request_g1.caching_l3_cache_accesses true
  Error:
  l3_request_g1.caching_l3_cache_accesses: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'
Fixes c43ca5091a37 ("perf/x86/amd: Add support for AMD NB and L2I "uncore" counters")
Signed-off-by Kim Phillips <[email protected]>
Signed-off-by Borislav Petkov <[email protected]>
Acked-by Peter Zijlstra <[email protected]>
Cc [email protected]
Link https://lkml.kernel.org/r/[email protected] open here
arch/x86/events/amd/uncore.c +7 -10
index a6ea07f2aa84..4d867a752f0e 100644
@@ -190,15 +190,12 @@ static int amd_uncore_event_init(struct perf_event *event)
 
 	/*
 	 * NB and Last level cache counters (MSRs) are shared across all cores
-	 * that share the same NB / Last level cache. Interrupts can be directed
-	 * to a single target core, however, event counts generated by processes
-	 * running on other cores cannot be masked out. So we do not support
-	 * sampling and per-thread events.
+	 * that share the same NB / Last level cache.  On family 16h and below,
+	 * Interrupts can be directed to a single target core, however, event
+	 * counts generated by processes running on other cores cannot be masked
+	 * out. So we do not support sampling and per-thread events via
+	 * CAP_NO_INTERRUPT, and we do not enable counter overflow interrupts:
 	 */
-	if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
-		return -EINVAL;
-
-	/* and we do not enable counter overflow interrupts */
 	hwc->config = event->attr.config & AMD64_RAW_EVENT_MASK_NB;
 	hwc->idx = -1;
 

@@ -306,7 +303,7 @@ static struct pmu amd_nb_pmu = {
 	.start		= amd_uncore_start,
 	.stop		= amd_uncore_stop,
 	.read		= amd_uncore_read,
-	.capabilities	= PERF_PMU_CAP_NO_EXCLUDE,
+	.capabilities	= PERF_PMU_CAP_NO_EXCLUDE | PERF_PMU_CAP_NO_INTERRUPT,
 };
 
 static struct pmu amd_llc_pmu = {

@@ -317,7 +314,7 @@ static struct pmu amd_llc_pmu = {
 	.start		= amd_uncore_start,
 	.stop		= amd_uncore_stop,
 	.read		= amd_uncore_read,
-	.capabilities	= PERF_PMU_CAP_NO_EXCLUDE,
+	.capabilities	= PERF_PMU_CAP_NO_EXCLUDE | PERF_PMU_CAP_NO_INTERRUPT,
 };
 
 static struct amd_uncore *amd_uncore_alloc(unsigned int cpu)
maintainer
#1 lore raw
Quoted 36 lines · On Mon, Mar 16, 2020 at 01:59:49PM +0100, [email protected] wrote:

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f967140dfb7442e2db0868b03b961f9c59418a1b Mon Sep 17 00:00:00 2001
From: Kim Phillips <[email protected]>
Date: Wed, 11 Mar 2020 14:13:21 -0500
Subject: [PATCH] perf/amd/uncore: Replace manual sampling check with CAP_NO_INTERRUPT flag

Enable the sampling check in kernel/events/core.c::perf_event_open(), which returns the more appropriate -EOPNOTSUPP.

BEFORE:

 $ sudo perf record -a -e instructions,l3_request_g1.caching_l3_cache_accesses true
 Error:
 The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (l3_request_g1.caching_l3_cache_accesses).
 /bin/dmesg | grep -i perf may provide additional information.

With nothing relevant in dmesg.

AFTER:

 $ sudo perf record -a -e instructions,l3_request_g1.caching_l3_cache_accesses true
 Error:
 l3_request_g1.caching_l3_cache_accesses: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'
Quoted 6 lines
Fixes c43ca5091a37 ("perf/x86/amd: Add support for AMD NB and L2I "uncore" counters")
Signed-off-by Kim Phillips <[email protected]>
Signed-off-by Borislav Petkov <[email protected]>
Acked-by Peter Zijlstra <[email protected]>
Cc [email protected]
Link https://lkml.kernel.org/r/[email protected] open here

I've worked around not having PERF_PMU_CAP_NO_EXCLUDE on older kernels and queued this patch for 4.19-4.4.

Signature · 2 lines
Thanks,
Sasha