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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 822ABC433FE for ; Wed, 20 Oct 2021 15:23:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5978861359 for ; Wed, 20 Oct 2021 15:23:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230369AbhJTP0A (ORCPT ); Wed, 20 Oct 2021 11:26:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229570AbhJTPZ5 (ORCPT ); Wed, 20 Oct 2021 11:25:57 -0400 Received: from mail-pf1-x430.google.com (mail-pf1-x430.google.com [IPv6:2607:f8b0:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21063C061749 for ; Wed, 20 Oct 2021 08:23:43 -0700 (PDT) Received: by mail-pf1-x430.google.com with SMTP id v8so3228634pfu.11 for ; Wed, 20 Oct 2021 08:23:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=9G/tgOu2U++uQPjqj0kkd4nYpGihFaCQehhixgnnnLM=; b=FdohNWF0lePfGiRKbumHGZsAGaLjjDCPzFQFJ5ok+qZV3MvXQXsTce3m8nzuOrUnOr HttiXl3VBBlg2SEnXtxSdhhz7nt7n32i+kurO9oz+oBp7/JUPLTfrw8bVeIzI8il5S7y +Su1eI0BuwtFDay0O0erLFi3b/nM3KpBQZVvhdsPE7Gp/4mGxEFqpqGmj9rBVgryz6BN SaPNpOoiKt0kp6fO0TlMNeoK0ocPWI1b1P11Y8XNcreX1k1KK3F385FOV+dWpZEiNGVx 5/jrgrsNrsP+j27vJioi2jBsc8BHASyJCxdF9Sg4ljAVZm8zss22Mwm4hbaf1v0w9NTN w+JQ== 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=9G/tgOu2U++uQPjqj0kkd4nYpGihFaCQehhixgnnnLM=; b=lZqrUTa3u9SY8nuC9s3rt/uHTQvnfIy+959jSlqeK0y5v9MasVkWGSJ+PXZEmnmjt2 DEQeFhqpj+kpQbF4qpBbVZvxyZfxiInErrZ/n/RrPK+nlyjlWd8gdaPTFyGQj9F+QZTZ bx40JwbpeCLC+H3cgExC/sPwKXovhL8YnoRNJt7xDd6ojBRcwO0/wDmFDVbhyw+/cOaH M3M44tOMKmno5OAXQzKp7kQXtipH/beMmtt74m0p7auUh2hi4U6Z5/CM7aN2rI2u7IgW 1W3UbJUmCQWNUO4om39hB3G9dEzpUDk+Ldsfx1CWpWMjJc/onZ2KoMVUyqUspvtO3FIY 0D8A== X-Gm-Message-State: AOAM531jWwMxteCUS8VrjVAlr0KPrZdJfknCS+LDdmfXMbqfX2vq9SM4 s8wRxuazTfh/kf0Mx20CXTsgKi79l2yx7Re4ZA8hxA== X-Google-Smtp-Source: ABdhPJxMcqpB7sT6+TEBLZlfW/zH2N29UinV40wClq1lYF1N0TvyDt6Cn320FsJLqNSwctbV9rFqwmrYd7zmA3a7PEk= X-Received: by 2002:a65:6499:: with SMTP id e25mr91668pgv.146.1634743422326; Wed, 20 Oct 2021 08:23:42 -0700 (PDT) MIME-Version: 1.0 References: <20211020013153.4106001-1-kaleshsingh@google.com> <20211020013153.4106001-3-kaleshsingh@google.com> <20211019222756.1fde436b@gandalf.local.home> <20211020111301.0032a43d@gandalf.local.home> In-Reply-To: <20211020111301.0032a43d@gandalf.local.home> From: Kalesh Singh Date: Wed, 20 Oct 2021 08:23:31 -0700 Message-ID: Subject: Re: [PATCH v2 2/5] tracing: Add division and multiplication support for hist triggers To: Steven Rostedt Cc: Suren Baghdasaryan , Hridya Valsaraju , Namhyung Kim , "Cc: Android Kernel" , Jonathan Corbet , Ingo Molnar , Shuah Khan , Masami Hiramatsu , Tom Zanussi , "open list:DOCUMENTATION" , LKML , "open list:KERNEL SELFTEST FRAMEWORK" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 20, 2021 at 8:13 AM Steven Rostedt wrote: > > On Wed, 20 Oct 2021 07:54:59 -0700 > Kalesh Singh wrote: > > > Is it worth adding something like this for the multiplication case as well? > > No, multiplication is a pretty fast operation, and the added branches to > test would cause more overhead than what you would save. But, division is a > very slow operation, and I believe that even with the extra branches it > would still help. > > If we do this, it should be a separate patch anyway, where we can actual do > measurements to see if there was an improvement, and revert if not. Sounds good. Thanks for the clarification Steve. - Kalesh > > -- Steve