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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 257C0C43217 for ; Wed, 16 Mar 2022 16:18:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357475AbiCPQTw (ORCPT ); Wed, 16 Mar 2022 12:19:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357471AbiCPQTs (ORCPT ); Wed, 16 Mar 2022 12:19:48 -0400 Received: from mail-yb1-xb36.google.com (mail-yb1-xb36.google.com [IPv6:2607:f8b0:4864:20::b36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 030076D3BA for ; Wed, 16 Mar 2022 09:18:24 -0700 (PDT) Received: by mail-yb1-xb36.google.com with SMTP id w16so5266378ybi.12 for ; Wed, 16 Mar 2022 09:18:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=/HhoL8quUY1FIjbb7RmxlmM5K/jdJ3Woo4L6/mprIUE=; b=p+Aa8cRpHOfTbwjkAxVbY0urZU45sfqEQfLLhtafoy5rvILOUdEMS6y9rfs7MCELML DB4AIlZrxW83Geb8g3qWcQ9llIp7QdPh9sekp5Orp3K7mUHx/Et4fB2A3GHFV61BSJsv EH8TBeLexL296mBDZMR/KRDgvhbzKfUi00BVIQJ0Eax5IuIU1m/iPUm5dJmwFWXOkM3V 7IklxZS/IT+8+gb9ijPL3RUP9USJwNh4RoTIGIBgQn8bxyM6BxqUlrZXJHucQt/xphED RQu8Wn+CJ9Hf8jlxoItdWdZCkGctnjcGF/X+WVT2vjiEZqaYG3QO1GxtbtaZTfe95HBT f9ZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=/HhoL8quUY1FIjbb7RmxlmM5K/jdJ3Woo4L6/mprIUE=; b=y39yc+NRdZALTrs5Wv3WY94U0no7MKUtt7Y05IeLKFT/ywLIxGhYLHeM6+ALkD6+b6 XtgqBQhGMW2fzSNDkciJUe0TgHIx51Q0+1EWGRqA250gsmKk7zpD1CtfGnjEaVmD1GyL my7WjiDTI2v81YhrK4MSIPefzD93M8R0sZFkUSqXjeX7LRzdAATASVJCEPZxFEdAV70l Ep6oZVsV25k7K5fGo6N1deu/VbI9C7UfsbrmsMygi4NJ+2APpbV2OCiNc6ADfDEzXjTy yA3zwA4qCjt8SDOEqxez7Pz4CYT/qijtI4jNoXeAdUVkN/6CM3efQOn/XfMMU40zTlm8 cqQg== X-Gm-Message-State: AOAM531Px6julHMpjGT0ZdJWJ4+SpAHPo5bTf7aRlq8fB3nYAWTDkONj es5dZCdvmji7pKaGTIF681XVJqtDpsHgZ7Pp3C0= X-Google-Smtp-Source: ABdhPJzKQMoIw0sLnRfxnDMBo7qlHDQw8nqkyk1ZtN4Dm7MPAuwp5+oY5yL2HaDo4CHjsFNIm8uQEYOjwHdZk/Ko0Uo= X-Received: by 2002:a25:8b03:0:b0:628:8cff:ed6c with SMTP id i3-20020a258b03000000b006288cffed6cmr624370ybl.513.1647447503528; Wed, 16 Mar 2022 09:18:23 -0700 (PDT) MIME-Version: 1.0 References: <20220315073949.7541-1-jiangshanlai@gmail.com> <20220315073949.7541-5-jiangshanlai@gmail.com> In-Reply-To: From: Lai Jiangshan Date: Thu, 17 Mar 2022 00:18:12 +0800 Message-ID: Subject: Re: [PATCH V3 4/7] x86/entry: move PUSH_AND_CLEAR_REGS out of error_entry To: Peter Zijlstra Cc: LKML , X86 ML , Borislav Petkov , Lai Jiangshan , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Dave Hansen , "H. Peter Anvin" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 16, 2022 at 11:07 PM Peter Zijlstra wrote: > > So I don't much care about the orc data, that's only used when > unwinding, a relatively rare occasion, anyway. But the text increase > does bother me a little, this can blow up I$ misses on syscall heavy > workloads. It has nothing to do with the syscall. It does add a lot in I$. But it is fortunate that the footprint is the same (before and after the patch) for a single exception vector. For example heavy #PF workloads. Footprint will increase after this patch when two or more exception vectors happen heavily at the same time, for example when #PF and timer are occurring heavily. We can put PUSH_AND_CLEAR_REGS in a single function to reduce the footprint for heavy multi-exception workloads. What do you think?