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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 3CDB2C43441 for ; Fri, 9 Nov 2018 19:44:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0517920883 for ; Fri, 9 Nov 2018 19:44:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0517920883 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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 S1727813AbeKJF0P (ORCPT ); Sat, 10 Nov 2018 00:26:15 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42100 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725752AbeKJF0P (ORCPT ); Sat, 10 Nov 2018 00:26:15 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7D48C811D5; Fri, 9 Nov 2018 19:44:13 +0000 (UTC) Received: from treble (ovpn-124-61.rdu2.redhat.com [10.10.124.61]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5DBDD5D736; Fri, 9 Nov 2018 19:44:11 +0000 (UTC) Date: Fri, 9 Nov 2018 13:44:09 -0600 From: Josh Poimboeuf To: Steven Rostedt Cc: Andy Lutomirski , Andy Lutomirski , Ingo Molnar , LKML , X86 ML , Ard Biesheuvel , Peter Zijlstra , Thomas Gleixner , Linus Torvalds , Masami Hiramatsu , Jason Baron , Jiri Kosina , David Laight , Borislav Petkov Subject: Re: [PATCH RFC 0/3] Static calls Message-ID: <20181109194409.mnrzdee6gh4ujutm@treble> References: <20181109072811.GB86700@gmail.com> <20181109152139.zig45f6gp24btfbc@treble> <20181109164137.5cngbfrkm4ihj4ra@treble> <20181109134241.5f4ce3be@gandalf.local.home> <979DB163-EFBD-41BB-8481-155AAF526E72@amacapital.net> <20181109143703.5f2205bf@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20181109143703.5f2205bf@gandalf.local.home> User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Fri, 09 Nov 2018 19:44:14 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 09, 2018 at 02:37:03PM -0500, Steven Rostedt wrote: > On Fri, 9 Nov 2018 11:05:51 -0800 > Andy Lutomirski wrote: > > > > Not sure what Andy was talking about, but I'm currently implementing > > > tracepoints to use this, as tracepoints use indirect calls, and are a > > > prime candidate for static calls, as I showed in my original RFC of > > > this feature. > > > > > > > > > > Indeed. > > > > Although I had assumed that tracepoints already had appropriate jump label magic. > > It does. But that's not the problem I was trying to solve. It's that > tracing took a 8% noise dive with retpolines when enabled (hackbench > slowed down by 8% with all the trace events enabled compared to all > trace events enabled without retpoline). That is, normal users (those > not tracinng) are not affected by trace events slowing down by > retpoline. Those that care about performance when they are tracing, are > affected by retpoline, quite drastically. > > I'm doing another test run and measurements, to see how the unoptimized > trampolines help, followed by the trampoline case. Are you sure you're using unoptimized? Optimized is the default on x86-64 (with my third patch). -- Josh