From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 546222F7462 for ; Tue, 28 Apr 2026 19:06:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777403162; cv=none; b=P7zswktdcxHvYRo4ZkgyqgzX+ipJapYwj37lXD1NxoSdggJErhSr+7eFzZx6Nmq6ZPjDhJykBaBqMzRwm+3YpbC9vVjAu+B7gwQWWrLEaWhYxtGeb7mp3YQE1U3PxX/fcmhSayVKt9Mo/LHUQVBhXD8fvcAeg/MGHKYD2QXkpAk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777403162; c=relaxed/simple; bh=EXtj03jSDONSwz7ojbd64U9/7N12tpyPL8IuZ92DU0c=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WBDDa2G8QYRcokZ+/fBoxctPj5hRKY9WixgSk5+QyXtU6UZ08F0AKPlWm22ZR+KHtiHr8nJMhKh/nloDeXYg715gowrvkPXFCRODCedMfwxEunxbDbYYiLg+LbAUaCuP87LjebxpPtzZQix2ams0tbIEONtadsVANHt5LwNXW7Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=XBwBhWQd; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XBwBhWQd" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1777403160; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Vbo6rUbYhvVjP5B0b4LhysdFlQMM84qaqHnlVngSXo0=; b=XBwBhWQd+GVxbtAhCqsjHBQomoDzivKtxvA5UlasJ+9n6Os53DG0WGAwfWKlm8mARmIYjG YbRd7YfIMbFLzL1tnklC8ME06x+MZC/QYbBWFpHIeS7FJVvQCfcBe29BxpG522KPeN6Udf x4Dv64eJVv1SuU8HVU6AkpDHDw6T1IQ= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-258-oST_kWqkMKiya5LBtHs2fw-1; Tue, 28 Apr 2026 15:05:57 -0400 X-MC-Unique: oST_kWqkMKiya5LBtHs2fw-1 X-Mimecast-MFC-AGG-ID: oST_kWqkMKiya5LBtHs2fw_1777403155 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7D6A11800473; Tue, 28 Apr 2026 19:05:54 +0000 (UTC) Received: from 192.168.0.21 (unknown [10.22.80.105]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 8E2D819560AB; Tue, 28 Apr 2026 19:05:48 +0000 (UTC) Date: Tue, 28 Apr 2026 16:05:47 -0300 From: Wander Lairson Costa To: Steven Rostedt Cc: Peter Zijlstra , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Valentin Schneider , Masami Hiramatsu , Mathieu Desnoyers , Andrew Morton , "open list:SCHEDULER" , "open list:TRACING" , acme@kernel.org, williams@redhat.com, gmonaco@redhat.com Subject: Re: [PATCH v3 1/4] tracing/preemptirq: Optimize preempt_disable/enable() tracepoint overhead Message-ID: References: <20260311125021.197638-1-wander@redhat.com> <20260311125021.197638-2-wander@redhat.com> <20260311193503.GS606826@noisy.programming.kicks-ass.net> <20260313090404.GK606826@noisy.programming.kicks-ass.net> <20260428145151.3860aa04@gandalf.local.home> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260428145151.3860aa04@gandalf.local.home> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 On Tue, Apr 28, 2026 at 02:51:51PM -0400, Steven Rostedt wrote: > On Fri, 13 Mar 2026 12:36:10 -0300 > Wander Lairson Costa wrote: > > > On Fri, Mar 13, 2026 at 10:04:04AM +0100, Peter Zijlstra wrote: > > > On Thu, Mar 12, 2026 at 02:19:15PM -0300, Wander Lairson Costa wrote: > > > > > > > > That's significant bloat, for really very little gain. Realistically > > > > > nobody is going to need these. > > > > > > > > > > > > > Of course, I can't speak for others, but more than once I debugged issues > > > > that those tracepoints had made my life far easier. Those cases convinced > > > > me that such a feature would be worth it. But if you don't see > > > > value and will reject the patches no matter what, nothing can be done, > > > > and I will have to accept defeat. > > > > > > If distros are going to enable this, I suppose I'm not going to stop > > > this. But I do very much worry about the general bloat of things, there > > > are a *LOT* of preempt_{dis,en}able() sites. > > > > > > > We plan to enable these tracepoints in the RHEL kernel-rt to track > > extended non-preemptible states that cause high latencies. These > > issues occasionally surface in customer OpenShift deployments, where > > deploying a custom debug kernel is highly impractical. Having these > > tracepoints available in the distribution kernel would be handful for > > debugging these production systems. That said, I expect enabling this > > feature to be the exception rather than the rule — most distribution > > kernels would leave it disabled. > > Is this work going to continue? Or should I just change the status to > "reject" in patchwork? > Yes, I am still working on it and should have a v4 soon. > -- Steve >