From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1011C32789 for ; Tue, 6 Nov 2018 23:36:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 245812086A for ; Tue, 6 Nov 2018 23:36:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 245812086A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=davemloft.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731061AbeKGJEb (ORCPT ); Wed, 7 Nov 2018 04:04:31 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:55442 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730409AbeKGJEa (ORCPT ); Wed, 7 Nov 2018 04:04:30 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::cf9]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 61BC81090B255; Tue, 6 Nov 2018 15:36:48 -0800 (PST) Date: Tue, 06 Nov 2018 15:36:47 -0800 (PST) Message-Id: <20181106.153647.1701013551426767213.davem@davemloft.net> To: ast@fb.com Cc: songliubraving@fb.com, dsahern@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Kernel-team@fb.com, ast@kernel.org, daniel@iogearbox.net, peterz@infradead.org, acme@kernel.org Subject: Re: [RFC perf,bpf 5/5] perf util: generate bpf_prog_info_event for short living bpf programs From: David Miller In-Reply-To: <27fc8327-3390-ba5a-6063-89c9e7165e7b@fb.com> References: <6C5A9FBD-F50D-444C-9038-E9557EC850D2@fb.com> <27fc8327-3390-ba5a-6063-89c9e7165e7b@fb.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 06 Nov 2018 15:36:48 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alexei Starovoitov Date: Tue, 6 Nov 2018 23:29:07 +0000 > I think concerns with perf overhead from collecting bpf events > are unfounded. > I would prefer for this flag to be on by default. I will sit in userspace looping over bpf load/unload and see how the person trying to monitor something else with perf feels about that. Really, it is inappropriate to turn this on by default, I completely agree with David Ahern. It's hard enough, _AS IS_, for me to fight back all of the bloat that is in perf right now and get it back to being able to handle simple full workloads without dropping events.. Every new event type like this sets us back. If people want to monitor new things, or have new functionality, fine. But not by default, please.