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=-15.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 0FB5DC433DB for ; Thu, 4 Feb 2021 10:58:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD14C64F39 for ; Thu, 4 Feb 2021 10:58:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235386AbhBDK6K (ORCPT ); Thu, 4 Feb 2021 05:58:10 -0500 Received: from foss.arm.com ([217.140.110.172]:55976 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235346AbhBDK6J (ORCPT ); Thu, 4 Feb 2021 05:58:09 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EB101D6E; Thu, 4 Feb 2021 02:57:23 -0800 (PST) Received: from [10.57.60.124] (unknown [10.57.60.124]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DF72B3F73B; Thu, 4 Feb 2021 02:57:19 -0800 (PST) Subject: Re: [PATCH v2 6/7] perf cs-etm: Detect pid in VMID for kernel running at EL2 To: Leo Yan Cc: Arnaldo Carvalho de Melo , Mathieu Poirier , Mike Leach , Jonathan Corbet , Alexander Shishkin , John Garry , Will Deacon , Peter Zijlstra , Ingo Molnar , Mark Rutland , Jiri Olsa , Namhyung Kim , Daniel Kiss , Denis Nikitin , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Al Grant References: <20210202163842.134734-1-leo.yan@linaro.org> <20210202163842.134734-7-leo.yan@linaro.org> <20210204040021.GF11059@leoy-ThinkPad-X240s> From: Suzuki K Poulose Message-ID: Date: Thu, 4 Feb 2021 10:57:06 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210204040021.GF11059@leoy-ThinkPad-X240s> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 2/4/21 4:00 AM, Leo Yan wrote: > On Tue, Feb 02, 2021 at 11:29:47PM +0000, Suzuki Kuruppassery Poulose wrote: >> On 2/2/21 4:38 PM, Leo Yan wrote: >>> From: Suzuki K Poulose >>> >>> The PID of the task could be traced as VMID when the kernel is running >>> at EL2. Teach the decoder to look for VMID when the CONTEXTIDR (Arm32) >>> or CONTEXTIDR_EL1 (Arm64) is invalid but we have a valid VMID. >>> >>> Cc: Mike Leach >>> Cc: Mathieu Poirier >>> Cc: Al Grant >>> Co-developed-by: Leo Yan >>> Signed-off-by: Suzuki K Poulose >>> Signed-off-by: Leo Yan >>> --- >>> .../perf/util/cs-etm-decoder/cs-etm-decoder.c | 32 ++++++++++++++++--- >>> 1 file changed, 28 insertions(+), 4 deletions(-) >>> >>> diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c >>> index 3f4bc4050477..fb2a163ff74e 100644 >>> --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c >>> +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c >>> @@ -6,6 +6,7 @@ >>> * Author: Mathieu Poirier >>> */ >>> +#include >>> #include >>> #include >>> #include >>> @@ -491,13 +492,36 @@ cs_etm_decoder__set_tid(struct cs_etm_queue *etmq, >>> const ocsd_generic_trace_elem *elem, >>> const uint8_t trace_chan_id) >>> { >>> - pid_t tid; >>> + pid_t tid = -1; >>> + u64 pid_fmt; >>> + int ret; >>> - /* Ignore PE_CONTEXT packets that don't have a valid contextID */ >>> - if (!elem->context.ctxt_id_valid) >>> + ret = cs_etm__get_pid_fmt(trace_chan_id, &pid_fmt); >>> + if (ret) >> >> Is this something we can cache in this function ? e.g, >> static u64 pid_fmt; >> >> if (!pid_pfmt) >> ret = cs_etm__get_pid_fmt(trace_chan_id, &pid_fmt); >> >> As all the ETMs will be running at the same exception level. > > Sorry that I let you repeated your comments again. > > To be honest, I considered this after read your comment in the previous > series, but I thought it's possible that multiple CPUs have different > PID format, especially for big.LITTLE arch. After read your suggestion > again, I think my concern is not valid, even for big.LITTLE, all CPUs > should run on the same kernel exception level. > > So will follow up your suggestion to cache "pid_fmt". No problem. > >> >>> + return OCSD_RESP_FATAL_SYS_ERR; >>> + >>> + /* >>> + * Process the PE_CONTEXT packets if we have a valid contextID or VMID. >>> + * If the kernel is running at EL2, the PID is traced in CONTEXTIDR_EL2 >>> + * as VMID, Bit ETM_OPT_CTXTID2 is set in this case. >>> + */ >>> + switch (pid_fmt) { >>> + case BIT(ETM_OPT_CTXTID): >>> + if (elem->context.ctxt_id_valid) >>> + tid = elem->context.context_id; >>> + break; >>> + case BIT(ETM_OPT_CTXTID2) | BIT(ETM_OPT_CTXTID): >> >> I would rather fix the cs_etm__get_pid_fmt() to return either of these >> as commented. i.e, ETM_OPT_CTXTID or ETM_OPT_CTXTID2. Thus we don't >> need the this case. > > I explained why I set both bits for ETM_OPT_CTXTID and ETM_OPT_CTXTID2 > in the patch 05/07. Could you take a look for it? I have responded to the comment in the patch. > >> With the above two addressed: >> >> Reviewed-by: Suzuki K Poulose > Thanks Suzuki