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=-4.0 required=3.0 tests=BAYES_00,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 BC3BBC433EF for ; Wed, 22 Sep 2021 19:34:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A285A6103C for ; Wed, 22 Sep 2021 19:34:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237217AbhIVTgD (ORCPT ); Wed, 22 Sep 2021 15:36:03 -0400 Received: from mail-lf1-f53.google.com ([209.85.167.53]:37726 "EHLO mail-lf1-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237186AbhIVTgC (ORCPT ); Wed, 22 Sep 2021 15:36:02 -0400 Received: by mail-lf1-f53.google.com with SMTP id i4so16269636lfv.4 for ; Wed, 22 Sep 2021 12:34:32 -0700 (PDT) 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=2Vnkrcw4DR2JdIAuglIphbFW5KXKuuI/s8yEeAhjVjE=; b=BatiLWrhX5hWvh9w0Kx+RnN0M74cPJ+DkoqVAQrttYYBkuA3Hx68momTXIpXphRYCh qKWDcI3JQTUsSl6h0O827zEtkGnCLWnjtgFkexVspApAUm+XVyPjDtS69iKjk2oWPpM/ gC6VQI/aMALo5mR/BVS6asK7ML3sSpzrWAH/FHbz01/2djVjJIbGjSfUbItvNp+YokIY 5Xu3BjAtUl05NhNJEtetWljNSsQHPcDKZ4h8j6enrJk5eN4p9LN5GLErr9hi+7OTcToz 1BGiBQCUmQk+5oRvVnAYoieCK9/REmcXpV+zy5JuUGbLr8YV59Ur3TNNmsSfR3Hp07wL f0pg== X-Gm-Message-State: AOAM532PmC4tXyMDJ5hkrndRDaM0JMpuLF5s82xnDBWlr+IrlByFsiQG QR5ZEtm9AHtSZpETYkY5IVP719mt7NJLGIjZ+BgKWY7f X-Google-Smtp-Source: ABdhPJwKEAxF1wD1uwICkEz5isiffF5KrNIHWcoWcC4H6gOoFM5+pECQVFRb9lzMIk072bT+lpIxAzu83Mh5VTlD1Fg= X-Received: by 2002:a05:6512:128f:: with SMTP id u15mr650392lfs.528.1632339271292; Wed, 22 Sep 2021 12:34:31 -0700 (PDT) MIME-Version: 1.0 References: <20210908172420.879240-1-namhyung@kernel.org> In-Reply-To: From: Namhyung Kim Date: Wed, 22 Sep 2021 12:34:20 -0700 Message-ID: Subject: Re: [PATCH v2] perf/core: Add a new read format to get a number of lost samples To: Peter Zijlstra Cc: Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , LKML , Stephane Eranian , Andi Kleen , Ian Rogers , Michael Petlan , Jiri Olsa Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter, On Fri, Sep 10, 2021 at 3:40 PM Namhyung Kim wrote: > > On Fri, Sep 10, 2021 at 2:42 PM Jiri Olsa wrote: > > > > On Wed, Sep 08, 2021 at 10:24:20AM -0700, Namhyung Kim wrote: > > > Sometimes we want to know an accurate number of samples even if it's > > > lost. Currenlty PERF_RECORD_LOST is generated for a ring-buffer which > > > might be shared with other events. So it's hard to know per-event > > > lost count. > > > > > > Add event->lost_samples field and PERF_FORMAT_LOST to retrieve it from > > > userspace. > > > > hi, > > looks good.. will there be some tools/perf change using this? > > Sure, I'll work on the userspace part after this is merged. > I'm thinking about adding LOST_SAMPLES records at the end > of the data section as if they came from the kernel. Can I get your feedback? Thanks, Namhyung