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=-8.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_MUTT 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 5CEF2C04AB5 for ; Thu, 6 Jun 2019 20:11:09 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 336CE2053B for ; Thu, 6 Jun 2019 20:11:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="hzO/xDx/"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="IjqYZZYq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 336CE2053B 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+infradead-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=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=JanLwKudOMVaVqon6i15Y5wHCAiO3IK7knvqZFWy3aw=; b=hzO/xDx/XL5XF2 K/Pth7Sc6ssc84YrBy0ofnaGTBwT0zGZ6lY7qqhzvAknQ83K0qt35EseNfKKbaA/DD/GKh/rBMiU5 AG4BLOgd7gFm02Ik94UwaR1zGstpeKSGBGMK5lHtoUq0mqIAGgtOBYB/EmVYgPEeKlvB8/bw977NL 2t4Dq/CrWgF0yiCX1ubGaj39AkqKQEMZ8uT+KsxMxm6uStsdaIjAxapF493wnc40xp6TB0fRT7lAF 8FhFiWNTeMs/TUgAFiEuC1iJTVxx3fI4RP5nPtWlg7f9oSZTdvIN4Iy8AkjbxFPtLbbdBM2vLVqG5 zeIp4VT0ozzDtFNoqZEQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hYyj1-0006NF-N4; Thu, 06 Jun 2019 20:11:03 +0000 Received: from merlin.infradead.org ([2001:8b0:10b:1231::1]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hYyiz-0006N2-P9 for linux-arm-kernel@bombadil.infradead.org; Thu, 06 Jun 2019 20:11:01 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=duYNpd7u6NCsl3zgH8XpP5ZaEHzH4usCoWirRor+tVo=; b=IjqYZZYq4+dfV/Anc1w3bBTif vGYMzDp6qJw2FWqFuUqwWCaHyoC4nHVXNffavdi6mEulkmqFQ530Q0zIvcT3RHKXxuzycyeBQoZBk L8Td/uVDlFIvOfI3i7zsncwVFYae/1Q9hrs7V6HoYoUX5dVfs4hl0fReghgGEHtP9B6uFfLJd2QbD DIVrz8C/s24DYZa6KrlYV6BWNdCtQzkXNhKXHfG9RnU/N4FTD1PXuCwCTFKcvcvoI4Rgk0ISG5toq yZXvXgpKrX7Wqfmw03NHF2saq2hE/PMdXaL7Gp6UNH3FLURl1tY1ZA3RgkRGgB48VInykFwkfIrXL qPeqLLF/Q==; Received: from [190.15.121.82] (helo=quaco.ghostprotocols.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hYyix-0005fj-EY; Thu, 06 Jun 2019 20:10:59 +0000 Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 0A63E41149; Thu, 6 Jun 2019 17:10:57 -0300 (-03) Date: Thu, 6 Jun 2019 17:10:56 -0300 From: Arnaldo Carvalho de Melo To: Mathieu Poirier Subject: Re: [PATCH] perf tools: Properly set the value of 'old' and 'head' in snapshot mode Message-ID: <20190606201056.GJ21245@kernel.org> References: <20190605161633.12245-1-mathieu.poirier@linaro.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190605161633.12245-1-mathieu.poirier@linaro.org> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.11.3 (2019-02-01) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: suzuki.poulose@arm.com, peterz@infradead.org, linux-kernel@vger.kernel.org, alexander.shishkin@linux.intel.com, mingo@redhat.com, leo.yan@linaro.org, jolsa@redhat.com, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Em Wed, Jun 05, 2019 at 10:16:33AM -0600, Mathieu Poirier escreveu: > This patch adds the necessay intelligence to properly compute the value > of 'old' and 'head' when operating in snapshot mode. That way we can get > the latest information in the AUX buffer and be compatible with the > generic AUX ring buffer mechanic. Leo, have you had the chance to test/review this one? Suzuki? I also changed the subject to: [PATCH] perf cs-etm: Properly set the value of 'old' and 'head' in snapshot mode So that when looking at a 'git log --oneline' one can have the proper context and know that its about cs-etm. - Arnaldo > Signed-off-by: Mathieu Poirier > --- > tools/perf/arch/arm/util/cs-etm.c | 127 +++++++++++++++++++++++++++++- > 1 file changed, 123 insertions(+), 4 deletions(-) > > diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c > index 911426721170..0a278bbcaba6 100644 > --- a/tools/perf/arch/arm/util/cs-etm.c > +++ b/tools/perf/arch/arm/util/cs-etm.c > @@ -31,6 +31,8 @@ struct cs_etm_recording { > struct auxtrace_record itr; > struct perf_pmu *cs_etm_pmu; > struct perf_evlist *evlist; > + int wrapped_cnt; > + bool *wrapped; > bool snapshot_mode; > size_t snapshot_size; > }; > @@ -536,16 +538,131 @@ static int cs_etm_info_fill(struct auxtrace_record *itr, > return 0; > } > > -static int cs_etm_find_snapshot(struct auxtrace_record *itr __maybe_unused, > +static int cs_etm_alloc_wrapped_array(struct cs_etm_recording *ptr, int idx) > +{ > + bool *wrapped; > + int cnt = ptr->wrapped_cnt; > + > + /* Make @ptr->wrapped as big as @idx */ > + while (cnt <= idx) > + cnt++; > + > + /* > + * Free'ed in cs_etm_recording_free(). Using realloc() to avoid > + * cross compilation problems where the host's system supports > + * reallocarray() but not the target. > + */ > + wrapped = realloc(ptr->wrapped, cnt * sizeof(bool)); > + if (!wrapped) > + return -ENOMEM; > + > + wrapped[cnt - 1] = false; > + ptr->wrapped_cnt = cnt; > + ptr->wrapped = wrapped; > + > + return 0; > +} > + > +static bool cs_etm_buffer_has_wrapped(unsigned char *buffer, > + size_t buffer_size, u64 head) > +{ > + u64 i, watermark; > + u64 *buf = (u64 *)buffer; > + size_t buf_size = buffer_size; > + > + /* > + * We want to look the very last 512 byte (chosen arbitrarily) in > + * the ring buffer. > + */ > + watermark = buf_size - 512; > + > + /* > + * @head is continuously increasing - if its value is equal or greater > + * than the size of the ring buffer, it has wrapped around. > + */ > + if (head >= buffer_size) > + return true; > + > + /* > + * The value of @head is somewhere within the size of the ring buffer. > + * This can be that there hasn't been enough data to fill the ring > + * buffer yet or the trace time was so long that @head has numerically > + * wrapped around. To find we need to check if we have data at the very > + * end of the ring buffer. We can reliably do this because mmap'ed > + * pages are zeroed out and there is a fresh mapping with every new > + * session. > + */ > + > + /* @head is less than 512 byte from the end of the ring buffer */ > + if (head > watermark) > + watermark = head; > + > + /* > + * Speed things up by using 64 bit transactions (see "u64 *buf" above) > + */ > + watermark >>= 3; > + buf_size >>= 3; > + > + /* > + * If we find trace data at the end of the ring buffer, @head has > + * been there and has numerically wrapped around at least once. > + */ > + for (i = watermark; i < buf_size; i++) > + if (buf[i]) > + return true; > + > + return false; > +} > + > +static int cs_etm_find_snapshot(struct auxtrace_record *itr, > int idx, struct auxtrace_mmap *mm, > - unsigned char *data __maybe_unused, > + unsigned char *data, > u64 *head, u64 *old) > { > + int err; > + bool wrapped; > + struct cs_etm_recording *ptr = > + container_of(itr, struct cs_etm_recording, itr); > + > + /* > + * Allocate memory to keep track of wrapping if this is the first > + * time we deal with this *mm. > + */ > + if (idx >= ptr->wrapped_cnt) { > + err = cs_etm_alloc_wrapped_array(ptr, idx); > + if (err) > + return err; > + } > + > + /* > + * Check to see if *head has wrapped around. If it hasn't only the > + * amount of data between *head and *old is snapshot'ed to avoid > + * bloating the perf.data file with zeros. But as soon as *head has > + * wrapped around the entire size of the AUX ring buffer it taken. > + */ > + wrapped = ptr->wrapped[idx]; > + if (!wrapped && cs_etm_buffer_has_wrapped(data, mm->len, *head)) { > + wrapped = true; > + ptr->wrapped[idx] = true; > + } > + > pr_debug3("%s: mmap index %d old head %zu new head %zu size %zu\n", > __func__, idx, (size_t)*old, (size_t)*head, mm->len); > > - *old = *head; > - *head += mm->len; > + /* No wrap has occurred, we can just use *head and *old. */ > + if (!wrapped) > + return 0; > + > + /* > + * *head has wrapped around - adjust *head and *old to pickup the > + * entire content of the AUX buffer. > + */ > + if (*head >= mm->len) { > + *old = *head - mm->len; > + } else { > + *head += mm->len; > + *old = *head - mm->len; > + } > > return 0; > } > @@ -586,6 +703,8 @@ static void cs_etm_recording_free(struct auxtrace_record *itr) > { > struct cs_etm_recording *ptr = > container_of(itr, struct cs_etm_recording, itr); > + > + zfree(&ptr->wrapped); > free(ptr); > } > > -- > 2.17.1 -- - Arnaldo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel