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[2620:137:e000::3:5]) by mx.google.com with ESMTPS id h70-20020a638349000000b005891f742957si1179437pge.570.2023.10.02.08.20.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Oct 2023 08:20:57 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:5 as permitted sender) client-ip=2620:137:e000::3:5; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:5 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by groat.vger.email (Postfix) with ESMTP id 48584808AB91; Mon, 2 Oct 2023 08:08:49 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at groat.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237853AbjJBPIi convert rfc822-to-8bit (ORCPT + 99 others); Mon, 2 Oct 2023 11:08:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237788AbjJBPIh (ORCPT ); Mon, 2 Oct 2023 11:08:37 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 43583A7; Mon, 2 Oct 2023 08:08:34 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36EC7C433C7; Mon, 2 Oct 2023 15:08:33 +0000 (UTC) Date: Mon, 2 Oct 2023 11:09:35 -0400 From: Steven Rostedt To: Christian Loehle Cc: Zheng Yejian , mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH] tracing: document buffer_size_kb more precisely Message-ID: <20231002110935.2fde6637@gandalf.local.home> In-Reply-To: References: X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on groat.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (groat.vger.email [0.0.0.0]); Mon, 02 Oct 2023 08:08:50 -0700 (PDT) On Tue, 26 Sep 2023 11:38:14 +0100 Christian Loehle wrote: > >> @@ -191,7 +191,7 @@ of ftrace. Here is a list of some of the key files: > >>       A few extra pages may be allocated to accommodate buffer management > >>       meta-data. If the last page allocated has room for more bytes > >>       than requested, the rest of the page will be used, > >> -    making the actual allocation bigger than requested or shown. > >> +    making the actual allocation bigger than requested. > > > > Hi, the actual allocation should still be bigger than shown due to the > > loss of accuracy when doing unit conversion from bytes to kilobytes (see > > tracing_entries_read()). > > > Right, the sysfs obviously only allows for KB aligned setting, but you're right. > If set on the cmdline non-KB multiples are possible and accuracy is lost. > Nevermind then. I'm assuming this patch can be dropped? -- Steve