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 D80C428DB54; Thu, 2 Jul 2026 23:01:53 +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=1783033314; cv=none; b=n/KjppHAScU9oA4264DySYnXA1ddTALGySmJSoleJtYKkgLaBHdE+L6qeohcD88aUvgzFbzA+ghmaukrJYIMaSPfl+NpXbDwPpBa0Jng8RSW9zT+XD71oKtwMFXJfmnQglKVtkW2NBM0WKOd9Rzz1jr9jOJPEtRSVmlt4rDcDfY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783033314; c=relaxed/simple; bh=vc7zLtHorRduHvMkQ0qDlCGVRUzu5bUilomtxkkGgf0=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=N6X9sKWXpULn1wc2lkYAfaCSmFRWZyAwbgJcu2VyuG1XZIaqmsjBUlq+uZCCK9AzDxheDCSDDXW7/TW/a6cHFw7gO4LPkQhIrWXGvywz1yCb/A5vHhv2bRhsP6wGO53RY03zGZG8qyYtZcgocN01VYeogWLPnydA/RzLgSeT/Y8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=URVLJy2Z; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="URVLJy2Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4CAA91F000E9; Thu, 2 Jul 2026 23:01:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1783033313; bh=ArRdQ3PAA6YKNFCjpWwE8Lbmu/1rYpWbZ9KDsz4OLK8=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=URVLJy2ZI76hZRymwYnjed5vgOTYdtDdw4bVtHf3SVHJwsBApgw5BV85Q7vgWQoa5 X0WuUdXAPUOej3NLdRZS/E1VcSkJyltxgUZfQppgusd9FOL+Ckyip0fzdTt+jQ2upc z37VCbjg8zICp22+xi0Uk2/kSfPsqJJdnIoVhFoQ= Date: Thu, 2 Jul 2026 16:01:52 -0700 From: Andrew Morton To: Cc: , , , , , Subject: Re: [PATCH 0/3 v3] delaytop: add delay max, timestamp and sorting for top latency analysis Message-Id: <20260702160152.ab0a3dea97e06652cf4874ac@linux-foundation.org> In-Reply-To: <20260702205704180NZ3cu_QF04KfBIL6vjTHL@zte.com.cn> References: <20260702205704180NZ3cu_QF04KfBIL6vjTHL@zte.com.cn> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 2 Jul 2026 20:57:04 +0800 (CST) wrote: > Previously delaytop only showed average delays. This patch adds: > > 1. delay_max fields to track the maximum delay value for each delay type > (cpu, blkio, irq, swapin, freepages, thrashing, compact, wpcopy) > per task. > > 2. The -t/--type option displays only the specified delay type with avg/max > values side by side, allowing focused analysis: > delaytop -t cpu # Show only CPU delay with avg/max > delaytop -t wpcopy # Show Copy-on-Write delay with avg/max > > 3. Wall-clock timestamp when each maximum delay occurred, displayed in the > MAX_TIMESTAMP column when using -t/--type option. This enables: > - Identifying the time when a process experienced an abnormal delay max > - Correlating delay max across multiple processes at the same timestamp > - Cross-referencing with logs, traces, or other metrics at that time > > 4. When using -t/--type option, tasks are sorted by maximum delay value in > descending order (largest delay first), enabling quick identification of > top N processes with highest delay spikes. Seems useful, thanks - I'll queue this for testing. AI review might have found a couple of things: https://sashiko.dev/#/patchset/20260702205704180NZ3cu_QF04KfBIL6vjTHL@zte.com.cn