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 18108351C27; Thu, 1 Oct 2026 00:20:59 +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=1790814061; cv=none; b=WxPRoudf0jKfDoXpn77lsCfMPRNivft3jFr4tw49WgYGrWxE5KqyFTdbcPEQwxZ6XJ4ts6GWFqqTJtarqvRNpPcPuNIjJ6CTsamGnJ/8cISdGNb4zb9SeP+HwKg6g84VORh9bX2czA/3yYkVTnERW12s5fG12pAHSrjVgduy/Nw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790814061; c=relaxed/simple; bh=yuxORQlGnMOpW40kkc3YnhipWX5peIfy6092QZ5/UMY=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References; b=ln4Y/j9Nag1+9muSTyl7BR3QQerrIqN9/t+LhUzyL206ZWrx6X9RohMrYX4ccD4Pd85lHYPb4FtM/+2DQlU7vCg8HXVeZuYK98rqawVsraqOFGnpbnF+oSFfhh69giswetJ1Zl8TgUXH2n0NobFL8MvPcXdLLG2fcE12neCol2Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dylWqnLb; 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="dylWqnLb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 402971F00899; Thu, 1 Oct 2026 00:20:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790814059; bh=seO9E854noC/3LuUfYHeeC5yA+NY/bP6dH3CPl3Ojno=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=dylWqnLbxwpki/jkNGcysEtewyGj20XNw+Op3O/Uuc07cculTfxK9beJ9lpao25EN qhCi8T78RJv7dC5lFg+V5CQ+hzOPW9zs3cUzRoqFRiayYsNVcBu0oYm46rn3wi1zo4 C6EXWKMgYJP2AqRV2eEAAjIImvDrFAHxdVik296WHiYF9XwAcRpMfIU/OFcITk7QkA G1ZeWRv0NSfr0eoMjX/l7RWqih4QFENnR+RXKA/YLnKGBXpakjVHaezSUB2IpY/SPO 4C2Xi9jL7im6OQWBnTjovmr454cvtrtcQSG1vEYRJoWg1KxaoCI5TlemeZLptcilYJ jG4KMNFmaaVpw== Date: Wed, 30 Sep 2026 14:20:58 -1000 Message-ID: <7335927f4aeb61a7b92066aa58d45446@kernel.org> From: Tejun Heo To: Tao Cui Cc: josef@toxicopanda.com, axboe@kernel.dk, cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, andrii@kernel.org, eddyz87@gmail.com, ast@kernel.org, daniel@iogearbox.net, linux-kselftest@vger.kernel.org, Tao Cui , ameryhung@gmail.com, alexei.starovoitov@gmail.com Subject: Re: [RFC PATCH v8 3/4] blk-iocost: add iocost_ioc_tick tracepoint for per-period device summary In-Reply-To: <20260930075154.189958-4-cui.tao@linux.dev> References: <20260930075154.189958-1-cui.tao@linux.dev> <20260930075154.189958-4-cui.tao@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Hello, Tao. The following is a Claude-generated review. On Wed, 30 Sep 2026 15:51:53 +0800, Tao Cui wrote: > Add iocost_ioc_tick, emitted once per period from the tail of > ioc_timer_fn() with the overall controller state: period_us, vrate, > busy_level, active iocg count, usage percentage and running state. > It fires every period the controller is running, including steady > states, plus one final tick before the controller goes idle, which > makes dormancy (e.g. a device saturated entirely by uncharged IO) > directly visible. ... > + __entry->running = ioc->running; The timer only runs while ioc->running is IOC_RUNNING and the switch to IOC_IDLE happens after the trace call, so this field always reads running except when racing ioc_rqos_exit(). The final tick before going idle reads active=0 running=1, and dormancy is only visible through the ticks stopping, not through the field. Can you either drop the field or report list_empty(&ioc->active_iocgs), and adjust the description? The event is also emitted before the vrate adjustment and the period transition, not from the tail of the function. Thanks. -- tejun