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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 3EF14C3A589 for ; Tue, 20 Aug 2019 17:58:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 14A2B214DA for ; Tue, 20 Aug 2019 17:58:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=dxuuu.xyz header.i=@dxuuu.xyz header.b="u/h/8wag"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="qHI9RYdR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730142AbfHTR6w (ORCPT ); Tue, 20 Aug 2019 13:58:52 -0400 Received: from new1-smtp.messagingengine.com ([66.111.4.221]:58267 "EHLO new1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730006AbfHTR6w (ORCPT ); Tue, 20 Aug 2019 13:58:52 -0400 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailnew.nyi.internal (Postfix) with ESMTP id 4B0572306; Tue, 20 Aug 2019 13:58:51 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute4.internal (MEProxy); Tue, 20 Aug 2019 13:58:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dxuuu.xyz; h= content-transfer-encoding:content-type:in-reply-to:date:cc :subject:from:to:message-id; s=fm1; bh=V4une9T0118s6OifTGsDx9LZN fb9kvaUaj3F5fzCd6s=; b=u/h/8wagkBqbj7O1gfNDI6T3iHd4N7OLnI4UqEIaO CcqaChfePnM4TAKcYL//5qqXszmzzEsA+oiRM7kih/BoozHdJubnyoHUqmH9F4fo kWO3B6508q5RHyk++s5InpcR4eEAvXsKCugSwDEcYmTgpMDZcQDsB9ymVnK32akF utXA3DwabE4rinHpUe5Su4gmNXKTN+Q/Ou9Kpho9WrVsar9WgQ29YidpyAf76lxu GqhczZ91RH3UrZ5N1G6Jhv+iImhaLUI4LIxHRqeiecU6ZOscwyQzMLm+vElDz9AA drRyTx9e+Gp4orejB5jIsRD2o+VWhM7EW4IexF8ilVclg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:in-reply-to:message-id:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=V4une9 T0118s6OifTGsDx9LZNfb9kvaUaj3F5fzCd6s=; b=qHI9RYdRSVkSETgw2uClzL 70JdXB3P9BAa3CEUS0wdk44jOd+ooIGmy9pdHqKZvxBj+pg+XozH774egLl6SpYc rXObo+cAx30IBp+AdmqpBsYDLnwZjqfomOS2KbYMqzI5IDP3+8WVeVV9HcEMP+La 623Ka39vuy6R2gjN75INol0b8XfJBMt+Go/O4Eoj2c8riiwi4R3IMz8Uu157dljC JyFhM37ydPj0CeXadQmqxW8gQz0KUD253yOqIYpIRRBQv8EojnpZiALFnrJY/w1z Cuh1lvdf8gompasWN3D6SpELAsuZmVyAKeg9z1pjplYPkgJVcNIPyZvoMiBXOIJQ == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduvddrudeguddguddujecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd enfghrlhcuvffnffculdejtddmnecujfgurhepgfgtjgffuffhvffksehtqhertddttdej necuhfhrohhmpedfffgrnhhivghlucgiuhdfuceougiguhesugiguhhuuhdrgiihiieqne cukfhppeduleelrddvtddurdeigedrvdenucfrrghrrghmpehmrghilhhfrhhomhepugig uhesugiguhhuuhdrgiihiienucevlhhushhtvghrufhiiigvpedt X-ME-Proxy: Received: from localhost (unknown [199.201.64.2]) by mail.messagingengine.com (Postfix) with ESMTPA id 30C1280064; Tue, 20 Aug 2019 13:58:48 -0400 (EDT) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 In-Reply-To: <20190820144503.GV2332@hirez.programming.kicks-ass.net> Date: Tue, 20 Aug 2019 10:58:47 -0700 Cc: , , , , , , , , , , , Subject: Re: [PATCH v3 bpf-next 1/4] tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE ioctl From: "Daniel Xu" To: "Peter Zijlstra" Message-Id: Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Hi Peter, On Tue Aug 20, 2019 at 4:45 PM Peter Zijlstra wrote: > On Fri, Aug 16, 2019 at 03:31:46PM -0700, Daniel Xu wrote: > > It's useful to know [uk]probe's nmissed and nhit stats. For example wit= h > > tracing tools, it's important to know when events may have been lost. > > debugfs currently exposes a control file to get this information, but > > it is not compatible with probes registered with the perf API. >=20 > What is this nmissed and nhit stuff? nmissed is the number of times the probe's handler should have been run but didn't. nhit is the number of times the probes handler has run. I've documented this information in the uapi header. If you'd like, I can put it in the commit message too. Daniel