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,URIBL_BLOCKED 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 9D46FC0650F for ; Thu, 8 Aug 2019 22:32:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 30B29216C8 for ; Thu, 8 Aug 2019 22:32:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=dxuuu.xyz header.i=@dxuuu.xyz header.b="NHtxErjw"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="EQyT/Rhe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404670AbfHHWc1 (ORCPT ); Thu, 8 Aug 2019 18:32:27 -0400 Received: from wout5-smtp.messagingengine.com ([64.147.123.21]:42265 "EHLO wout5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725535AbfHHWc0 (ORCPT ); Thu, 8 Aug 2019 18:32:26 -0400 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.west.internal (Postfix) with ESMTP id 68BF538C; Thu, 8 Aug 2019 18:32:25 -0400 (EDT) Received: from imap35 ([10.202.2.85]) by compute4.internal (MEProxy); Thu, 08 Aug 2019 18:32:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dxuuu.xyz; h= mime-version:message-id:in-reply-to:references:date:from:to:cc :subject:content-type; s=fm1; bh=QMLmMC2THUGZXMqoqN+1vqTXcyCXgy6 CcOzbwDdbEtY=; b=NHtxErjw0lvgJV1YcACxefTVaNCmTTguos85663wWyFBRNY 2RF4bI8YAhw2WugRYGIFuPF5ELOnrvSmwbgq51dPLlYJWHHtauzUAl1Ye8T4FIRY FX25RjP2wQRPMu4fnZzBSvZ/HfstsBh42ZitCPrX70jYzYpYXlhMUh2vq8U0MKAx 2N7SLi/3WQZvWPXJjqHvIVOpZS7AQ5Af0zKe8vIkjT1skGsyBXwdm5BhqvK5nyaC vM5VCNS4xVYZz1bVTCC0bXNvYhzhv23LWniDhf6OjJnpEnx0/imaYPMaMxnrD5PJ LAtq0E+2hjdUcMQb+lQ6rfzE9WrhO65Lk9FAj4Q== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=QMLmMC 2THUGZXMqoqN+1vqTXcyCXgy6CcOzbwDdbEtY=; b=EQyT/Rhesf/Xsd7poFm5Gh SpghYIDOemEfl9xEBntk/BQeGSYFMW11UE5CvGBnRwFJPMOKneCS4EsoerKcAxGX H41dD+eaDdbmdR6yPF6p089EWE6w//aq2y+SqZzkHbJ9cir7ujoGPh0AMsiN3V8X K5OpIauYQYonn+tB4AtWD4bQyhNDRmBu8+EmAxOlVmZhZmfbJ27kKXjHywT3O2// MDnWkrzP6fs6Kjbiyy9Z9GP0LdYrRAATCCQrQf5xGdzAgalCzdmSBI8D6GpVvpG1 5BrO8aXwBM+Zf3lPGGIgMdAvByQ0yin1nx9/g73hZQz5sf9Mai+JIXHBgwDVxEQg == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduvddrudduiedguddtucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne gfrhhlucfvnfffucdlfeehmdenucfjughrpefofgggkfgjfhffhffvufgtsehttdertder redtnecuhfhrohhmpedfffgrnhhivghlucgiuhdfuceougiguhesugiguhhuuhdrgiihii eqnecurfgrrhgrmhepmhgrihhlfhhrohhmpegugihusegugihuuhhurdighiiinecuvehl uhhsthgvrhfuihiivgeptd X-ME-Proxy: Received: by mailuser.nyi.internal (Postfix, from userid 501) id 91E7214C0062; Thu, 8 Aug 2019 18:32:24 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.1.6-808-g930a1a1-fmstable-20190805v2 Mime-Version: 1.0 Message-Id: In-Reply-To: References: <20190806233826.2478-1-dxu@dxuuu.xyz> Date: Thu, 08 Aug 2019 15:32:24 -0700 From: "Daniel Xu" To: "Andrii Nakryiko" Cc: "Song Liu" , "Yonghong Song" , "Andrii Nakryiko" , "bpf@vger.kernel.org" , "Kernel Team" Subject: Re: [PATCH 0/3] Add PERF_EVENT_IOC_QUERY_KPROBE ioctl Content-Type: text/plain Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, Aug 7, 2019, at 12:03 PM, Andrii Nakryiko wrote: > On Tue, Aug 6, 2019 at 4:39 PM Daniel Xu wrote: > > > > It's useful to know kprobe's nmissed and nhit stats. For example with > > Is nmissed/nhit kprobe-specific? What about tracepoints and raw > tracepoints, do they have something similar or they can never be > missed? At least nhit still seems useful, so would be nice to have > ability to get that with the same API, is it possible? > I'm still trying to grok all the tracepoint/ftrace machinery, but it appears to me like it is kprobe/uprobe specific. My guess is that b/c tracepoints are inline (and don't require trapping interrupts), it cannot really "miss". This brings up a good point, though. I think we want the same querying functionality for uprobes so it might be worthwhile to make this API generic. Something like PERF_EVENT_IOC_QUERY_PROBE so we can later add in uprobe stats. And maybe tracepoint if it makes sense. Thoughts?