From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 EEDA6138A; Sun, 31 Dec 2023 04:39:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (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="EEL4F3KZ" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Sender:Reply-To:Content-ID:Content-Description; bh=IVgiiMZDdOtzhHaKIlJ7lRKAgdbPHW0wrCohBZPxCWA=; b=EEL4F3KZtl41bZZKJ0d3hf/GgY r7VdpYBtVMkLrvW9l/yF8ppEMjk34MvQQKY1X0McrXzr6EK1NUdlOMy1ug3pOevIMgVFDkYnKToF7 9B0GK4VmTlhGrReZYbcTOi81JWqFVZjZfXyk2Fk4cQan1fHl1CxQ9YKuzbYWRPRVMKvkuU9cdQKf8 aoF/dMkLYxk5W83UmubMnXbFShjk6cySsQZPdbASM30J8uTYPOlm3+MT4gfcN6D8bL3vDVWKNeg2O x+9PeQgWFrw62aJ+JSrfehJYAmAXhWesJI+BtE+2Upjl22eUmqj8Z5awHTmwHHdksfwtDn3DWvk6N 6x0l8DFQ==; Received: from [50.53.46.231] (helo=[192.168.254.15]) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1rJnbZ-003wt9-1b; Sun, 31 Dec 2023 04:39:17 +0000 Message-ID: <4ad2944b-db65-4877-b388-2bcaa23e88ec@infradead.org> Date: Sat, 30 Dec 2023 20:39:16 -0800 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] ring-buffer/Documentation: Add documentation on buffer_percent file Content-Language: en-US To: Steven Rostedt , LKML , Linux Trace Kernel , linux-doc@vger.kernel.org, Jonathan Corbet Cc: Masami Hiramatsu , Mathieu Desnoyers References: <20231229122402.537eb252@gandalf.local.home> From: Randy Dunlap In-Reply-To: <20231229122402.537eb252@gandalf.local.home> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/29/23 09:24, Steven Rostedt wrote: > From: "Steven Rostedt (Google)" > > When the buffer_percent file was added to the kernel, the documentation > should have been updated to document what that file does. > > Acked-by: Masami Hiramatsu (Google) > Fixes: 03329f9939781 ("tracing: Add tracefs file buffer_percentage") > Signed-off-by: Steven Rostedt (Google) LGTM. Thanks. Acked-by: Randy Dunlap > --- > Changes since v2: https://lore.kernel.org/linux-trace-kernel/20231226130149.4685c838@gandalf.local.home > > - s/watermark/water-mark/ (Randy Dunlap) That comment is backwards. :) No new patch needed IMO. > > - Added '::' and indented the number list so that it has better > formatting (kernel test robot) > > Documentation/trace/ftrace.rst | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst > index 933e7efb9f1b..917501a2f348 100644 > --- a/Documentation/trace/ftrace.rst > +++ b/Documentation/trace/ftrace.rst > @@ -180,6 +180,21 @@ of ftrace. Here is a list of some of the key files: > Only active when the file contains a number greater than 0. > (in microseconds) > > + buffer_percent: > + > + This is the watermark for how much the ring buffer needs to be filled > + before a waiter is woken up. That is, if an application calls a > + blocking read syscall on one of the per_cpu trace_pipe_raw files, it > + will block until the given amount of data specified by buffer_percent > + is in the ring buffer before it wakes the reader up. This also > + controls how the splice system calls are blocked on this file:: > + > + 0 - means to wake up as soon as there is any data in the ring buffer. > + 50 - means to wake up when roughly half of the ring buffer sub-buffers > + are full. > + 100 - means to block until the ring buffer is totally full and is > + about to start overwriting the older data. > + > buffer_size_kb: > > This sets or displays the number of kilobytes each CPU -- #Randy