From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id X9mBAWlz3WeGgRYAWB0awg (envelope-from ) for ; Fri, 21 Mar 2025 10:10:49 -0400 Authentication-Results: simark.ca; dkim=pass (2048-bit key; unprotected) header.d=lists.lttng.org header.i=@lists.lttng.org header.a=rsa-sha256 header.s=default header.b=LgprClt0; dkim-atps=neutral Received: by simark.ca (Postfix, from userid 112) id CEAA51E100; Fri, 21 Mar 2025 10:10:48 -0400 (EDT) X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-25) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-3.1 required=5.0 tests=ARC_SIGNED,ARC_VALID,BAYES_00, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=4.0.1 Received: from lists.lttng.org (lists.lttng.org [158.69.130.29]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id DE84B1E0C0 for ; Fri, 21 Mar 2025 10:10:46 -0400 (EDT) ARC-Filter: OpenARC Filter v1.2.1 lists.lttng.org 4ZK49L3GnGz155Z ARC-Seal: i=1; d=lists.lttng.org; s=arc1; a=rsa-sha256; cv=none; t=1742566246; b=Om0jikGIMNXvuaR0WxhHSZGpl4gh/Ne6vybqUcaK/bLHXC2UVGQBv3f96RPoSdQhvinD VW6Z8pk5Gzsq15jTtHolBGSGmxudMHLBBUcr7fKvVN3z8IY/Gz3l8WHmb4GG68DhXNK6b gjLSCownU9kccCCY1drc9jlR1KyQLaXcg735ZZKTCZJ9jj2ydLftLGjXjW6DKLG6W/D/G wpHyM9qi/AScqSaXmyjTPFs7wOoufxUzSd9dXwrzk9xMkSolJd7DBJ7iGDsckJevSCG+i 4okGqmurTYUI5Cu6ulwVHfJUdMoLjP5tooRvzyyG4e5E/lmkV+RRAcoOiWTiyGpeHSg== ARC-Message-Signature: i=1; d=lists.lttng.org; s=arc1; a=rsa-sha256; c=relaxed/simple; t=1742566246; h=DKIM-Signature:To:Subject:Date:Message-ID:MIME-Version:From:From; bh=GnvvywXot0MwlHCmh81YQUgyXK7kauxhxVWdEgBMooQ=; b=f5n311eK30VM+9rEkqqUMc/JiDIV7FoZbf481dIkXD33wCakLZnHb3IhgILmvZGH6kw+ rJsS9ekC9hdL5k+3Qpc33f4WQfJz/N3zUaf0Tl18SQWN5X+92MoBC6qMEDfQc/XVaTOXk gfAX0F2WFNqyh1jaZ0025LBfnrmjJf1qSyc8M9nRkbQBBcF1fwKpVK3BSlnDSYWZgP9SC FmK/CNtH+cZSpZgFhHciryoQcMprY69GdERP3Q7QejWQvfqz9SnZro+gUNLBiJjQUi9dQ J/zZHeKk/TWueQgA/gWIOxfvTHjRefn17EsJylPVI/v02nIOgCet3PESehRBu77t2Jg== ARC-Authentication-Results: i=1; lists.lttng.org; arc=none smtp.remote-ip="::1" DKIM-Filter: OpenDKIM Filter v2.11.0 lists.lttng.org 4ZK49L3GnGz155Z DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.lttng.org; s=default; t=1742566246; bh=GnvvywXot0MwlHCmh81YQUgyXK7kauxhxVWdEgBMooQ=; h=To:Subject:In-Reply-To:References:Date:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=LgprClt0TNTSAvbvNzGpLWBM5l/g7Y/MTzNyLWOh3pQWrT2Azjcq9W4EGarHi8oj0 /1zl9vibsTWzy70Z2icdMFm1m7VEOJa3+2a39r7IQjQPW6wy1w07LOA/LJ0gPaB052 pOvi6iiWX0Zum2Oj1Z+w8nCN4lfssUu2spiPGCvJ42KvnZzWiJfxy8a+RXC5nMWcQN mfipEtb2g4UwlQ4QX7Q5IMsBYHD1ydxNDiCHIYQdeDRbe21yHRtFCBYM2Vk58d10yO mva+lSBA7ylvwnaLPM7w2Uf51oX5snUQ4LTbvcYWz17YXm8LkITWnTonqymtyjz3wo PHz5cYDgp7hKQ== Received: from lists-lttng01.efficios.com (localhost [IPv6:::1]) by lists.lttng.org (Postfix) with ESMTP id 4ZK49L3GnGz155Z; Fri, 21 Mar 2025 10:10:46 -0400 (EDT) ARC-Filter: OpenARC Filter v1.2.1 lists.lttng.org 4ZK49K3FFVz155Y DKIM-Filter: OpenDKIM Filter v2.11.0 lists.lttng.org 4ZK49K3FFVz155Y Received: from smtpout.efficios.com (smtpout.efficios.com [158.69.130.18]) by lists.lttng.org (Postfix) with ESMTPS id 4ZK49K3FFVz155Y for ; Fri, 21 Mar 2025 10:10:45 -0400 (EDT) Received: from localhost (199-193-172-8.cpe.axion.ca [199.193.172.8]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4ZK49J4qRcz42Z; Fri, 21 Mar 2025 10:10:44 -0400 (EDT) To: Kienan Stewart , Gour DEV , lttng-dev@lists.lttng.org Subject: Re: lttng-dev Digest, Vol 203, Issue 7 In-Reply-To: <09086109-a0fd-4b38-817e-b5bd2cbd9c2f@efficios.com> Organization: EfficiOS References: <605bbc18-bb08-4a72-b470-fc0c34e67acd@efficios.com> <09086109-a0fd-4b38-817e-b5bd2cbd9c2f@efficios.com> Date: Fri, 21 Mar 2025 10:10:44 -0400 Message-ID: <87pliamq3f.fsf@laura> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: lttng-dev@lists.lttng.org X-Mailman-Version: 2.1.39 Precedence: list List-Id: LTTng development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Olivier Dion via lttng-dev Reply-To: Olivier Dion Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" On Fri, 21 Mar 2025, Kienan Stewart via lttng-dev wrote: > Hi Lakshya, > > On 3/21/25 8:52 AM, Gour DEV wrote: >> Thanks Kienan for digging this and explaining the behaviour, [...] >> Also, I thought using --buffers-global >> >> would >> be better for me as I could know how much memory will be required but looks >> like that option is only available for kernel tracking, it would be very >> good if this option could be available for user buffering also, but that >> could come later. >> > > Global buffers for UST is planned for the next release. The trade-off of > using it is that tracing overhead will increase (as the buffers are no > longer per-CPU), but in exchange for a potentially lower memory > footprint particularly in situations where not all possible CPUs are online. > Little correction here. `--buffers-global' is the ownership of the buffers (UID vs PID vs system). The next release introduces the buffers allocation policies `per-{cpu,channel}'. Therefore `--buffers-global' will still be only available for the kernel domain, AFAIK. User-space however will be able to allocate a single ring-buffer for a given channel (actually it depends on the buffer ownership UID vs PID), thus reducing the amount of memory used, for that channel, by a factor proportional to the number of CPUs possible on the system. [...] Thanks, Olivier -- Olivier Dion EfficiOS Inc. https://www.efficios.com