LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Kim Phillips <kim.phillips@amd.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>,
	mingo@redhat.com, linux-kernel@vger.kernel.org,
	ak@linux.intel.com
Subject: [PATCH] perf/x86: Fix n_pair for cancelled txn
Date: Mon, 5 Oct 2020 10:25:16 +0200
Message-ID: <20201005082516.GG2628@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <fc89da87-6070-beda-2437-4089257c55aa@amd.com>

On Fri, Oct 02, 2020 at 04:10:42PM -0500, Kim Phillips wrote:
> Tested-by: Kim Phillips <kim.phillips@amd.com>

---
Subject: perf/x86: Fix n_pair for cancelled txn
From: Peter Zijlstra <peterz@infradead.org>
Date: Mon Oct  5 10:09:06 CEST 2020

Kan reported that n_metric gets corrupted for cancelled transactions;
a similar issue exists for n_pair for AMD's Large Increment thing.

The problem was confirmed and confirmed fixed by Kim using:

  sudo perf stat -e "{cycles,cycles,cycles,cycles}:D" -a sleep 10 &

  # should succeed:
  sudo perf stat -e "{fp_ret_sse_avx_ops.all}:D" -a workload

  # should fail:
  sudo perf stat -e "{fp_ret_sse_avx_ops.all,fp_ret_sse_avx_ops.all,cycles}:D" -a workload

  # previously failed, now succeeds with this patch:
  sudo perf stat -e "{fp_ret_sse_avx_ops.all}:D" -a workload

Fixes: 5738891229a2 ("perf/x86/amd: Add support for Large Increment per Cycle Events")
Reported-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Kim Phillips <kim.phillips@amd.com>
---
 arch/x86/events/core.c       |    6 +++++-
 arch/x86/events/perf_event.h |    1 +
 2 files changed, 6 insertions(+), 1 deletion(-)

--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1089,8 +1089,10 @@ static int collect_event(struct cpu_hw_e
 		return -EINVAL;
 
 	cpuc->event_list[n] = event;
-	if (is_counter_pair(&event->hw))
+	if (is_counter_pair(&event->hw)) {
 		cpuc->n_pair++;
+		cpuc->n_txn_pair++;
+	}
 
 	return 0;
 }
@@ -2062,6 +2064,7 @@ static void x86_pmu_start_txn(struct pmu
 
 	perf_pmu_disable(pmu);
 	__this_cpu_write(cpu_hw_events.n_txn, 0);
+	__this_cpu_write(cpu_hw_events.n_txn_pair, 0);
 }
 
 /*
@@ -2087,6 +2090,7 @@ static void x86_pmu_cancel_txn(struct pm
 	 */
 	__this_cpu_sub(cpu_hw_events.n_added, __this_cpu_read(cpu_hw_events.n_txn));
 	__this_cpu_sub(cpu_hw_events.n_events, __this_cpu_read(cpu_hw_events.n_txn));
+	__this_cpu_sub(cpu_hw_events.n_pair, __this_cpu_read(cpu_hw_events.n_txn_pair));
 	perf_pmu_enable(pmu);
 }
 
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -235,6 +235,7 @@ struct cpu_hw_events {
 					     they've never been enabled yet */
 	int			n_txn;    /* the # last events in the below arrays;
 					     added in the current transaction */
+	int			n_txn_pair;
 	int			assign[X86_PMC_IDX_MAX]; /* event to counter assignment */
 	u64			tags[X86_PMC_IDX_MAX];
 

  reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-30 14:29 [PATCH] perf/x86/intel: Fix n_metric for the canceled group kan.liang
2020-10-02 11:02 ` Peter Zijlstra
2020-10-02 13:16   ` Liang, Kan
2020-10-02 21:10     ` Kim Phillips
2020-10-05  8:25       ` Peter Zijlstra [this message]
2020-10-07 16:04         ` [tip: perf/core] perf/x86: Fix n_pair for cancelled txn tip-bot2 for Peter Zijlstra
2020-10-05  8:26     ` [PATCH] perf/x86: Fix n_metric " Peter Zijlstra
2020-10-07 16:04       ` [tip: perf/core] " tip-bot2 for Peter Zijlstra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201005082516.GG2628@hirez.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=ak@linux.intel.com \
    --cc=kan.liang@linux.intel.com \
    --cc=kim.phillips@amd.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git
	git clone --mirror https://lore.kernel.org/lkml/10 lkml/git/10.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git