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 EECBFC64EB4 for ; Fri, 30 Nov 2018 14:45:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B51AE2145D for ; Fri, 30 Nov 2018 14:45:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B51AE2145D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org 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 S1727096AbeLABy7 (ORCPT ); Fri, 30 Nov 2018 20:54:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:34850 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726645AbeLABy7 (ORCPT ); Fri, 30 Nov 2018 20:54:59 -0500 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6D01C20863; Fri, 30 Nov 2018 14:45:25 +0000 (UTC) Date: Fri, 30 Nov 2018 09:45:23 -0500 From: Steven Rostedt To: Jiri Olsa Cc: LKML , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , "Luis Claudio R. Goncalves" , Arnaldo Carvalho de Melo , ldv@altlinux.org, esyr@redhat.com, Frederic Weisbecker , Masami Hiramatsu , Namhyung Kim Subject: Re: Rough idea of implementing blocking perf calls for system call tracepoints Message-ID: <20181130094523.1bc91052@gandalf.local.home> In-Reply-To: <20181130140158.GD3617@krava> References: <20181128134700.212ed035@gandalf.local.home> <20181128141808.4b047976@gandalf.local.home> <20181130104044.GB3617@krava> <20181130114809.GC3617@krava> <20181130140158.GD3617@krava> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 30 Nov 2018 15:01:58 +0100 Jiri Olsa wrote: > > or perhaps just tracepoints.. does not seem to make much > > sense for he events > > actualy the syscalls seems to be enough for now ;-) I tried > something and ended up with hack below Actually, we *only* want to do syscalls. We really don't want to add blocking to trace events. That would be a nightmare for deadlocks and such. I was thinking about adding a PTRACE feature that makes this part of PTRACE. That is, we start this via PTRACE and let PTRACE signal the tracer process when the tracee process blocks, and it can then wake up the tracee process. A tracer must have PTRACE permissions anyway. The goal of this is to speed up syscall tracing. -- Steve