From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 80B421E32CF; Mon, 19 Jan 2026 10:02:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768816931; cv=none; b=Vyl5UPZp+5txFgzkGjNuFJjpLFgOA0GJv9kBsWBFLUT/clThlmIF+RmahFXbfFFsfLJ0jHcgRKEqKmMElCPtcZJTMNM3N4OXGvu0fKQra42hk7lB3ird7Qz1/9191N9Pvr+f3y6BUGowuLeXZgUmEBDJ7W+ZHZDJA/oSSj4PrKg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768816931; c=relaxed/simple; bh=pnEa4VrEeISlVZoQcuz8SHTYgHUKfSg2Cc8V9YYuxT4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sWkvC4Vuo4w0pKZ9Apjl5GuA0bny0GEPmz+ZSwOpcrAFUphtkUQAMfPkUEMZtguy+bNOE6xEULeZbw1eYozhaisOVt1BC0mosEPJC1F8q9JXHEOXy8TqNkQyVZ6AY/75pDPjyjBF6+6KC0no1C3/mKSN6W3ig3lsODAMUboHy+o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=hjdYwKDx; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="hjdYwKDx" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=qXOMWcP57YdkA+i9IBIoBnXaMzpom4V6rwMqCjGNerQ=; b=hjdYwKDxS2qcPazHW+3+Eqkkj3 YE6Zl81cEwSRwQNkfSYtmQUIp3fLXdoVA2KqhVer9zMQDAjHCq9fPkFgFUIXYJq0tBlrlbQ+JzrAt Xmud/79wL8FQL95xdKBstVSn2bwhcj8ZAhDp6BMxL81T9+1Og4GZWp8j9TtECYP7B5ZfdY9l/KVFn H7oYT4GzqgypFGLe8nj5sq4Rhy0CoGs1lUaBnFvK3UuA94Lf7sopB4AB9ukGZR3CzwElTjzpZdcmC yb/FitY8ldcGGlv1nOT9Drg9RfQxm/JwddZhUJEeWRJ5wRreAvXjhDgRJu7ogcuEKZC8Jk5SlDPtw WHSaoYeg==; Received: from 2001-1c00-8d85-5700-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:5700:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vhm4u-0000000D86P-2dgS; Mon, 19 Jan 2026 10:01:44 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 6D3B23006CD; Mon, 19 Jan 2026 11:01:43 +0100 (CET) Date: Mon, 19 Jan 2026 11:01:43 +0100 From: Peter Zijlstra To: Thomas Gleixner 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 Message-ID: <20260119100143.GO830755@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> <87zf6b19mt.ffs@tglx> Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87zf6b19mt.ffs@tglx> On Sun, Jan 18, 2026 at 11:46:18AM +0100, Thomas Gleixner wrote: > 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; D'0h. I suppose doing this makes more sense than fixing the script. Want me to write it up?