Received: by 2002:ad5:474a:0:0:0:0:0 with SMTP id i10csp863805imu; Fri, 9 Nov 2018 07:18:50 -0800 (PST) X-Google-Smtp-Source: AJdET5ehBjYDNH9Vw8HWvGr98MQie0mJegStFN2ohL77WzqkBeLlKgWLPl1qRHR9cnVoaGtCTrJR X-Received: by 2002:a17:902:2943:: with SMTP id g61-v6mr9456100plb.82.1541776730485; Fri, 09 Nov 2018 07:18:50 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1541776730; cv=none; d=google.com; s=arc-20160816; b=avPREHBpHcRclWkFL0bBnNX76i3uW9FlTuGYpA3sBhb8cFrqHDBRNrR6z+WVAvZU/5 +9F550yauw0bsBJvBIpU8+8t65ueBNHbb+BUMeolwSTi7ZlOHj+GrCN4v30f16dJekRj 2ckEMcwuotCg4sJQYwjGpTZcW7++Nxk46miP7vEat+lZebqnP7s29t23TdiT39OK2U0T uhwTRXGEfUJkbjwBtYeitdqCSoE/EeHs6KH+wgy2Cm44W3MEbt7XH7sNooLJ39ezvuFk p0Nj01rB0VsenH0IG5zra5ZBdHQirv6fhgB9B1HJmadVb8s73LtAYZSyFF0ibclL4n5u fdQA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:dkim-signature; bh=WaBlzxzS+GDCiqnZ0/Mh6MnWrYZN9nBbL8DUB34u2Ck=; b=kI+GQVhe28MubEmt6i6l1Ka7iRJ1U/FXhBZmctGv89oiTPWDj4YCHnXsKTr5bFzHQL o4/mMA48BOAVcqdh+SFEMiT+1MG2GDqQV8KOFuV7G1is8mGUICkyfoc4XSQZmNc7pyMt sOnkcKT7Btr90xQ+I0VTjq4Mvj7S+SYjzQEYOCnGKbiTyZmLfmsACJEI5rWZf/7AG6is S8Zzk4Hpr4/27J5Yy4jmuRTRNYQ+OIaLv/CkigmGKvoatSNFGSdGXRYD2OQgfRfEJMmq DScCX+EX5fb9VeK3NoycpIGXFaD9G4dpiV3eZj7/84W9VnJxwX5ot52RnSFhyObG3tdi aUMQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b="y/OjEtzQ"; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id v23-v6si7468248plo.182.2018.11.09.07.18.28; Fri, 09 Nov 2018 07:18:50 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b="y/OjEtzQ"; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728311AbeKJA5c (ORCPT + 99 others); Fri, 9 Nov 2018 19:57:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:50932 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727828AbeKJA5c (ORCPT ); Fri, 9 Nov 2018 19:57:32 -0500 Received: from mail-wm1-f53.google.com (mail-wm1-f53.google.com [209.85.128.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3E62C208E3 for ; Fri, 9 Nov 2018 15:16:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541776591; bh=WaBlzxzS+GDCiqnZ0/Mh6MnWrYZN9nBbL8DUB34u2Ck=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=y/OjEtzQcVq39oINKXhslHiHYL1wpab30/AyJIeBdkmRyo47TmviWGY92UruxOQG6 qI3C+MfeqAMClpE+V61qkeQ2RilMXAJ02E6sWX1qmKdzo7F++19dHtUHWPqrac7mSc LCFLhvhsbdCGKx7u92Bk+2jR3VxkEK/9hUjUqplI= Received: by mail-wm1-f53.google.com with SMTP id r63-v6so2357354wma.4 for ; Fri, 09 Nov 2018 07:16:31 -0800 (PST) X-Gm-Message-State: AGRZ1gItmBqJQxulMyVRNltQFsUox1GDj24m0a1/yePOPrVpgkij47je 6YJbhtKzpp7NnAiUY4zP4t/CfVrt6VdPsqwJLiCxXw== X-Received: by 2002:a1c:ccb:: with SMTP id 194-v6mr5452105wmm.102.1541776589693; Fri, 09 Nov 2018 07:16:29 -0800 (PST) MIME-Version: 1.0 References: <20181109072811.GB86700@gmail.com> In-Reply-To: <20181109072811.GB86700@gmail.com> From: Andy Lutomirski Date: Fri, 9 Nov 2018 07:16:17 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH RFC 0/3] Static calls To: Ingo Molnar Cc: Josh Poimboeuf , LKML , X86 ML , Ard Biesheuvel , Andrew Lutomirski , Steven Rostedt , Peter Zijlstra , Thomas Gleixner , Linus Torvalds , Masami Hiramatsu , Jason Baron , Jiri Kosina , David Laight , Borislav Petkov Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 8, 2018 at 11:28 PM Ingo Molnar wrote: > > > All other usecases are bonus, but it would certainly be interesting to > investigate the impact of using these APIs for tracing: that too is a > feature enabled everywhere but utilized only by a small fraction of Linux > users - so literally every single cycle or instruction saved or hot-path > shortened is a major win. For tracing, we'd want static_call_set_to_nop() or something like that, right? --Andy