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=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 DBF7DC43461 for ; Thu, 17 Sep 2020 10:22:49 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6D9DC2083B for ; Thu, 17 Sep 2020 10:22:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="zurnU9Ef"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="i8WVr5yZ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6D9DC2083B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Message-ID:References:In-Reply-To:Subject:To:From: Date:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=fuX6veaOw5J8/2dLBNt/Q4syIqnraYcFM+Kes+FO528=; b=zurnU9EfT/2FHZxdOlw/FGQy0 TbTtTxnGggsnF6UvrTN8UlVArkyiwk15PoiXsrTAK+biLHe08PMJEQRXUVLwnIeFsjmrsWhZUaL3G KVxpLmrDTHLK50waVGSVwORlMEe5t1VwIigamLRLLIOF+gT18kR+RV7Mr4AKJnHno/qH3VS2L0zlx Nwdf5Xqp7cD7XEVh0Iv1pUGR7uko0XDg0IOBK19pgBLdm4HcpA8Ivu7yTigdEXCaoWXhvfRiGM699 Ytq4GFu0e7ShmLJ2h9PDVCvLMGqwB4YbZK2MwGKgMGt9O7kzzLS3To1t17sDT2Zjz2h8Zj8fGHjLA c4VojW/qg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIr2b-0004xc-NB; Thu, 17 Sep 2020 10:21:25 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIr2W-0004va-1G for linux-arm-kernel@lists.infradead.org; Thu, 17 Sep 2020 10:21:23 +0000 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D1A9B2083B; Thu, 17 Sep 2020 10:21:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600338079; bh=C+KplrEy19xRRUCzs59Jn7lzDV7YqtFzKMiyU9gK+yI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=i8WVr5yZwKpsZGvL6XrCYnezlOKdPRuzdzLPVWVxY5sziJImifxeRFbKncXjR3ZYh hDQ3x08AKoF+glZUzcoFjBZ6H1GZl79IqOmnHvH98MzOeDgn+BjiE3BCg/1EMPNVJE Z3j+d9BzQduY+6RaFUmB6PZRL3HVHyP5YPqcPa6Q= Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1kIr2S-00CbMs-0V; Thu, 17 Sep 2020 11:21:17 +0100 MIME-Version: 1.0 Date: Thu, 17 Sep 2020 11:21:15 +0100 From: Marc Zyngier To: Leo Yan Subject: Re: [PATCHv3] perf kvm: add kvm-stat for arm64 In-Reply-To: <20200917101219.GD12548@leoy-ThinkPad-X240s> References: <20200917003645.689665-1-sergey.senozhatsky@gmail.com> <20200917100950.GC12548@leoy-ThinkPad-X240s> <20200917101219.GD12548@leoy-ThinkPad-X240s> User-Agent: Roundcube Webmail/1.4.8 Message-ID: <652f10660f09bd608b825233713f775a@kernel.org> X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: leo.yan@linaro.org, sergey.senozhatsky@gmail.com, acme@kernel.org, mark.rutland@arm.com, peterz@infradead.org, will@kernel.org, john.garry@huawei.com, mathieu.poirier@linaro.org, namhyung@kernel.org, suleiman@google.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200917_062120_231499_3E6F76F2 X-CRM114-Status: GOOD ( 21.53 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Mathieu Poirier , Peter Zijlstra , John Garry , linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Sergey Senozhatsky , Suleiman Souhlal , Namhyung Kim , Will Deacon , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2020-09-17 11:12, Leo Yan wrote: > Add Marc at this time, sorry for spamming. > > On Thu, Sep 17, 2020 at 06:09:50PM +0800, Leo Yan wrote: >> [ + Marc ] >> >> On Thu, Sep 17, 2020 at 09:36:45AM +0900, Sergey Senozhatsky wrote: >> >> [...] >> >> > diff --git a/tools/perf/arch/arm64/util/kvm-stat.c b/tools/perf/arch/arm64/util/kvm-stat.c >> > new file mode 100644 >> > index 000000000000..32e58576f186 >> > --- /dev/null >> > +++ b/tools/perf/arch/arm64/util/kvm-stat.c >> > @@ -0,0 +1,86 @@ >> > +// SPDX-License-Identifier: GPL-2.0 >> > +#include >> > +#include >> > +#include "../../util/evsel.h" >> > +#include "../../util/kvm-stat.h" >> > +#include "arm64_exception_types.h" >> > +#include "debug.h" >> > + >> > +define_exit_reasons_table(arm64_exit_reasons, kvm_arm_exception_type); >> > +define_exit_reasons_table(arm64_trap_exit_reasons, kvm_arm_exception_class); >> > + >> > +const char *kvm_trap_exit_reason = "esr_ec"; >> > +const char *vcpu_id_str = "id"; >> >> On Arm64, ftrace tracepoint "kvm_entry" doesn't contain the field "id" >> or field "vcpu_id", thus it always reads out the "id" is 0 and it is >> recorded into Perf's structure vcpu_event_record::vcpu_id and assigned >> to perf thread's private data "thread::private". >> >> With current code, it will not mess up different vcpus' samples >> because >> now the samples are analyzed based on thread context, but since all >> threads' "vcpu_id" is zero, thus all samples are accounted for >> "vcpu_id=0" and cannot print out correct result with option "--vcpu": >> >> >> $ perf kvm stat report --vcpu 4 >> >> Analyze events for all VMs, VCPU 4: >> >> VM-EXIT Samples Samples% Time% Min Time Max >> Time Avg time >> >> Total Samples:0, Total events handled time:0.00us. >> >> >> This is an issue I observed, if we want to support option "--vcpu", >> seems we need to change ftrace event for "kvm_entry", but this will >> break ABI. >> >> Essentially, this issue is caused by different archs using different >> format for ftrace event "kvm_entry", on x86 it contains feild >> "vcpu_id" but arm64 only just records "vcpu_pc". >> >> @Marc, @Will, do you have any suggestion for this? Do you think it's >> feasible to add a new field "vcpu_id" into the tracepoint "kvm_entry" >> for Arm64's version? The question really is: how will you handle the ABI breackage? I don't see a good solution for it, apart from having a *separate* tracepoint that collects all the information you need. And even that is really ugly. M. -- Jazz is not dead. It just smells funny... _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel