From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D362181AA8; Sat, 30 May 2026 20:41:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780173691; cv=none; b=MI5/yCwrgBeu176Kc9YKo1C5W+ipsdDD4R8ymY+r5WAGCW+T3aOhD1fSzE3dcYD856sJZUNGMTJQs7ukED85sWrtKnwfmtrRvP81N9NFRj4FC7n8g4VNndDH30HuzwTYggFMLSvvT+9xtcpnal5PQ9s8QXbxY+HsBfpysnQpPgs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780173691; c=relaxed/simple; bh=5By0w1qMomB+iNGthJymGH2cmhqfAJ67KL5GV70icwA=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=m3+17DtvEUSdz6OV4Bq0RK8EbTAiHzTzKKNbn7TOe7Q3C3mjZk4Y48AW+CIMRXtVWqOTbsaTLJOdjFohzjrrQ2wiH9klebp8N1kzm0iZCI60MWmXSaB2aI33MJiP7h4dYCE4MaXKKSMNksH4fYs3xuGUFw6036NQdl2F1ayC0i0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YZvU4B2q; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YZvU4B2q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4C7181F00893; Sat, 30 May 2026 20:41:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780173690; bh=LPsAOz3o1J7sRNOfDz3N6keDmlfcCiVqo3km4jbMTL0=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=YZvU4B2qWgLIeyyiTwYX7aXVzWeaf2I1dpv+o0KiqK1pDf/qKB+UqfEClTtrLMofQ BZ5kGlkHqTYbWCDjkUCMfkUecKmADIKHtnWPeSdE65x+9nVKpndi/78bdJAwpPYuFJ LJ8iQdU9sOrRENLZFbIPx79HQ3C+D7GWEOGBTu7I4PPNeu2busCE1cocwn0zTaTASB QTLkWlq+eSB11UfrlrkfJRKbLM/UNBQfg6oqkE/SAF0bSS8dJAC4jiHqkW+aD719Kp B66aUxmcGH4CXQXy0H7ea/bbO+5wfAosytlWndjEieaFlwUlwEFSVahUb17JSAa2Vv SEy1uSE5wESSA== From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 RESEND] perf/lock: enable end-timestamp accounting for cgroup aggregation Reply-To: sashiko-reviews@lists.linux.dev To: "Suchit Karunakaran" Cc: linux-perf-users@vger.kernel.org, bpf@vger.kernel.org In-Reply-To: <20260530195940.78700-1-suchitkarunakaran@gmail.com> References: <20260530195940.78700-1-suchitkarunakaran@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sat, 30 May 2026 20:41:29 +0000 Message-Id: <20260530204130.4C7181F00893@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [Medium] Incomplete lock contentions for per-CPU locks (spinlocks/rwlocks= ) are silently dropped when using cgroup aggregation due to an unmodified e= arly return in `account_end_timestamp()`. -- commit 9be2409410efd2d4d44f23abbecf590bbbc25d34 Author: Suchit Karunakaran perf/lock: enable end-timestamp accounting for cgroup aggregation This commit enables end-timestamp accounting for cgroup aggregation by tracking the cgroup_id in the BPF program during contention_begin. It updates update_lock_stat() in userspace and contention_end() in BPF to use this recorded cgroup context instead of fetching it dynamically. > diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_= lock_contention.c > index cbd7435579fea..1a5bd2ff8ee4c 100644 > --- a/tools/perf/util/bpf_lock_contention.c > +++ b/tools/perf/util/bpf_lock_contention.c > @@ -463,8 +463,8 @@ static void update_lock_stat(int map_fd, int pid, u64= end_ts, > stat_key.lock_addr_or_cgroup =3D ts_data->lock; > break; > case LOCK_AGGR_CGROUP: > - /* TODO */ > - return; > + stat_key.lock_addr_or_cgroup =3D ts_data->cgroup_id; > + break; > default: > return; > } [Severity: Medium] Since this patch enables end-timestamp accounting for cgroup aggregation, should the early return for LOCK_AGGR_CGROUP in account_end_timestamp() also be removed? tools/perf/util/bpf_lock_contention.c:account_end_timestamp() { ... /* Now it'll check per-cpu tstamp map which doesn't have TID. */ if (aggr_mode =3D=3D LOCK_AGGR_TASK || aggr_mode =3D=3D LOCK_AGGR_C= GROUP) return; ... } Without removing this check, incomplete lock contentions for per-CPU locks (like spinlocks and rwlocks) appear to be silently skipped when using cgroup aggregation. [ ... ] --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260530195940.7870= 0-1-suchitkarunakaran@gmail.com?part=3D1