From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 71B6C270545; Sun, 18 Jan 2026 10:46:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768733182; cv=none; b=bAy27LtafEDsZ7BojOr3JmQr8sbKxL2doxhe9o3u1kQUrWyoayx5/rJMbESlHXKUSJFxdJQ7Gxe8f8wXq6OYM9SkCIWCnwsZ244v/MlzzVoZrk5iqdddsCenxCDM6Q22+GQiyag+fyRuhNG9+/QZ+ShhxfYw/uW77+ciAORTdCQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768733182; c=relaxed/simple; bh=hjWpmmhs2PbYtYrxpNGcT9bMRDBbHRhLgGMxRablJaE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=dZArJPTSlMNCC954Kli8/KQYZvt3JGrfNZERHCgc4AYu5WxUs+fC3ygRt9nrPh9aWcqGBUVhgMqoRboQ025hG9dUAYk7YRt7GVq7Pw4nYorGV6vvSzWm6xX1kGcjPbOT2ODb9/O+7Mw2u9Ywi1fG8erjtLxfZGgs4o01DhHTAJ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WtoHKMgs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WtoHKMgs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7889AC116D0; Sun, 18 Jan 2026 10:46:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768733182; bh=hjWpmmhs2PbYtYrxpNGcT9bMRDBbHRhLgGMxRablJaE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=WtoHKMgsU4cYA82z07xFd8OTQElMXH9p6VOMq1eqFSAERDplwzUhxImUUdZ2P1R0k uFqnHFR5D12DUn1h4CNUalm9P6cybbsog1vJN8GKxnMIWt0ir0xIEl5q92UwDtoZLY HaHqN7PEXjZFU3gpsNMPZe4QnhiRvHeeeboBm/Fd3cBrZHKdowRS2c5VnfN8Xpo5xR XxH/7Smc2TY7gYInaNBQIlVhhVhi/cjkKWL0Qv7inZv+1C7Yh0FXws/irsuKgCV57E 2qQ+D5In6yWhTUKeq27xjpoURzs1AbtSLcDjGuhzuNs4axSmTtvB2YA9w8Zl3G8I20 D9L5fIBUMh1PQ== From: Thomas Gleixner To: Peter Zijlstra Cc: LKML , Mathieu Desnoyers , "Paul E. McKenney" , Boqun Feng , Jonathan Corbet , Prakash Sangappa , Madadi Vineeth Reddy , K Prateek Nayak , Steven Rostedt , Sebastian Andrzej Siewior , Arnd Bergmann , linux-arch@vger.kernel.org, Randy Dunlap , Ron Geva , Waiman Long Subject: Re: [patch V6 07/11] rseq: Implement time slice extension enforcement timer In-Reply-To: <20260116181524.GF831285@noisy.programming.kicks-ass.net> References: <20251215155615.870031952@linutronix.de> <20251215155709.068329497@linutronix.de> <20251218150524.GY3707837@noisy.programming.kicks-ass.net> <87ecorbccp.ffs@tglx> <20251219100517.GA1132199@noisy.programming.kicks-ass.net> <20260116181524.GF831285@noisy.programming.kicks-ass.net> Date: Sun, 18 Jan 2026 11:46:18 +0100 Message-ID: <87zf6b19mt.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Fri, Jan 16 2026 at 19:15, Peter Zijlstra wrote: > On Fri, Dec 19, 2025 at 11:05:17AM +0100, Peter Zijlstra wrote: > >> I was thinking that perhaps the hrtimer tracepoints, filtered on this >> specific timer, might just do. Arming the timer is the point where the >> extension is granted, cancelling the timer is on the slice_yield() (or >> any other random syscall :/), and the timer actually firing is on fail. > > Here, I google pasted this together. I don't actually speak much snake > (as you well know). Nor does it fully work; the handle_expire() thing is > busted, I definitely have expire entries in the trace, but they're not > showing up. You want the below. Then you get: Task: slice_test Mean: 350.266 ns Latency (us) | Count ------------------------------ EXPIRED | 238 0 us | 143189 1 us | 167 2 us | 26 3 us | 11 4 us | 28 5 us | 31 6 us | 22 7 us | 23 8 us | 32 9 us | 16 10 us | 35 Thanks tglx --- --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1742,7 +1742,7 @@ static void __run_hrtimer(struct hrtimer lockdep_assert_held(&cpu_base->lock); - debug_deactivate(timer); + debug_hrtimer_deactivate(timer); base->running = timer; /*