From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 36302246795 for ; Wed, 17 Sep 2025 09:01:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758099694; cv=none; b=ECVwl0C2CidBuHWMScJIOT9ySWoZMuKMD5DId9RvCh4aVoOb5tSpXUekG0cYejVwWArWgv08XWynB9dDTRli3XAPPmfdF1obafusIrTyxGq5SQSMdYW/x/f5cGsfzfi5XAF5+JRsoFJoo5rfghkLCbfJttlm4w1yc/V7Jd8a8bE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758099694; c=relaxed/simple; bh=d10jcmjqCyO6AfZM4juDsBEXkDMso64K6oL59Aqxowk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WpmzIgYhSAdyf8R+I/hEjw3lKFg9rEYUw9Awsj/dfWN4uofLj6+mD2izC1JA48hnwZwbGGA4Nbn+GoD7q+QE7V5PzsiwtGj+QhLGMt1WOO9ihFw/wsHQzE5FqYQY6GlEo4gbQ6DD0qNzzJZKcNQiJ513Eq1HJW/19INPm0D9s8M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=XHNyp+Zl; arc=none smtp.client-ip=148.163.156.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="XHNyp+Zl" Received: from pps.filterd (m0353729.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 58GLm2WZ032503; Wed, 17 Sep 2025 09:01:27 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=kexc49 TnL9QZdO8OTZ8yI9JGT5pMRQxNTKUlP99uYWU=; b=XHNyp+Zl/sGzz2MuWt79WT 1j6vMaUMleLiyD+PwZFzoLxZocf0Gs3fbpKeOX9Kj6H53+kUN9TUcO68TKZa8+qY Jm6zrd+PKoGssI1jLNH6fg/DQJRzZK0DvfH8cKl7UNL5/RI9FN/VTqSavinmitUP Cv0a58aMBVZCANsTbqrfK4SseZpROCDRaSa1eolAaAsKAdijP57jawZmZqhFOQio UlpZ9x5WHoWb3R5QUsugTpjC6iUUaqB+PJaqlbRwA96xxH9z98OjwRe91UbzrK2x dVVJL1rUxE5YKXCGhsbAqw55NvRUIEitYJ/GaEouUNReZBX/X0b/DH0MqV3o9xxA == Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 497g4hjh7m-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 17 Sep 2025 09:01:25 +0000 (GMT) Received: from m0353729.ppops.net (m0353729.ppops.net [127.0.0.1]) by pps.reinject (8.18.1.12/8.18.0.8) with ESMTP id 58H8vIPG031351; Wed, 17 Sep 2025 09:01:25 GMT Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 497g4hjh7e-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 17 Sep 2025 09:01:25 +0000 (GMT) Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 58H6kaWO027308; Wed, 17 Sep 2025 09:01:24 GMT Received: from smtprelay01.fra02v.mail.ibm.com ([9.218.2.227]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 495men894w-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 17 Sep 2025 09:01:24 +0000 Received: from smtpav05.fra02v.mail.ibm.com (smtpav05.fra02v.mail.ibm.com [10.20.54.104]) by smtprelay01.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 58H91JPq50397520 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Sep 2025 09:01:19 GMT Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CCE7720043; Wed, 17 Sep 2025 09:01:19 +0000 (GMT) Received: from smtpav05.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6CDA32004B; Wed, 17 Sep 2025 09:01:15 +0000 (GMT) Received: from [9.124.214.27] (unknown [9.124.214.27]) by smtpav05.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 17 Sep 2025 09:01:15 +0000 (GMT) Message-ID: Date: Wed, 17 Sep 2025 14:31:14 +0530 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V3 0/6] perf/tools: Add interface to expose vpa dtl To: Athira Rajeev , acme@kernel.org, jolsa@kernel.org, adrian.hunter@intel.com, maddy@linux.ibm.com, irogers@google.com, namhyung@kernel.org, linux-perf-users@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org, aboorvad@linux.ibm.com, sshegde@linux.ibm.com, hbathini@linux.vnet.ibm.com, Aditya.Bodkhe1@ibm.com, venkat88@linux.ibm.com, Tejas.Manhas1@ibm.com References: <20250916052536.93911-1-atrajeev@linux.ibm.com> Content-Language: en-US From: tejas05 In-Reply-To: <20250916052536.93911-1-atrajeev@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: onUkVePpjHgtHj5cK-Z6zUPE4V2dacgT X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwOTE2MDIwNCBTYWx0ZWRfX9mQB5+vMDAha yjJ7VNR1xpw/nlCLTG7hEqPK7riPWmQll5ymmzzkcajGYTklWUcocsflXgqt7IKLaT6p7U7JOOS mbJtEtkPBUvlBb7nWoBtd42jNGA7C7EWSvvMC2DOqLIWIA1aQ7vvdsppHSCIGzU52Wj0k1Hec1L 1IegP2yvOOAKKhi2OnR6ar6RcOFBZ/Uful06HtSyXBwG+4mH1woPS/HCF58bLxvJBNwjnJVOpi6 c1guR64gQ1DiR/bO4+Zrl0PMwhW1y+OtvtXIaZeKac0RS1Lt1zMVlZSonm/nCCreuDhgxUSvVJB o1CvIY41r1OMt9niMAR7DzjnJ0VkP5hccvB2IvJbpy7Ar31S57qtC3Xo9A2R8XuDgqIlQqb8AfJ P3ArGkdQ X-Proofpoint-GUID: wySdjwr5mvkF_X1D9yGoFX9sQ1Z9nzwc X-Authority-Analysis: v=2.4 cv=co2bk04i c=1 sm=1 tr=0 ts=68ca78e5 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=yJojWOMRYYMA:10 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=0L29NJCzZRmhsLPFlqIA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1117,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-09-16_02,2025-09-17_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 impostorscore=0 priorityscore=1501 suspectscore=0 adultscore=0 phishscore=0 malwarescore=0 spamscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2509160204 > The pseries Shared Processor Logical Partition(SPLPAR) machines can > retrieve a log of dispatch and preempt events from the hypervisor > using data from Disptach Trace Log(DTL) buffer. With this information, > user can retrieve when and why each dispatch & preempt has occurred. > The vpa-dtl PMU exposes the Virtual Processor Area(VPA) DTL counters > via perf. > > - Patch 1 to 6 is perf tools side code changes to enable perf > report/script on perf.data file > > Kernel and tools patches is separated. Kernel patches are posted here : > V2: https://lore.kernel.org/linux-perf-users/20250915072224.98958-1-atrajeev@linux.ibm.com/T/#t > V3: https://lore.kernel.org/linux-perf-users/2D40E056-6194-40CD-BF72-B474A3ACDCAA@linux.ibm.com/T/#t > > Infrastructure used > =================== > > The VPA DTL PMU counters do not interrupt on overflow or generate any > PMI interrupts. Therefore, hrtimer is used to poll the DTL data. The timer > interval can be provided by user via sample_period field in nano seconds. > vpa dtl pmu has one hrtimer added per vpa-dtl pmu thread. DTL (Dispatch > Trace Log) contains information about dispatch/preempt, enqueue time etc. > We directly copy the DTL buffer data as part of auxiliary buffer and it > will be processed later. This will avoid time taken to create samples > in the kernel space. The PMU driver collecting Dispatch Trace Log (DTL) > entries makes use of AUX support in perf infrastructure. On the tools side, > this data is made available as PERF_RECORD_AUXTRACE records. > > To corelate each DTL entry with other events across CPU's, an auxtrace_queue > is created for each CPU. Each auxtrace queue has a array/list of auxtrace buffers. > All auxtrace queues is maintained in auxtrace heap. The queues are sorted > based on timestamp. When the different PERF_RECORD_XX records are processed, > compare the timestamp of perf record with timestamp of top element in the > auxtrace heap so that DTL events can be co-related with other events > Process the auxtrace queue if the timestamp of element from heap is > lower than timestamp from entry in perf record. Sometimes it could happen that > one buffer is only partially processed. if the timestamp of occurrence of > another event is more than currently processed element in the queue, it will > move on to next perf record. So keep track of position of buffer to continue > processing next time. Update the timestamp of the auxtrace heap with the timestamp > of last processed entry from the auxtrace buffer. > > This infrastructure ensures dispatch trace log entries can be corelated > and presented along with other events like sched. > > vpa-dtl PMU example usage > > # ls /sys/devices/vpa_dtl/ > events format perf_event_mux_interval_ms power subsystem type uevent > > > To capture the DTL data using perf record: > > # ./perf record -a -e sched:*,vpa_dtl/dtl_all/ -c 1000000000 sleep 1 > > The result can be interpreted using perf report. Snippet of perf report -D: > > # ./perf report -D > > There are different PERF_RECORD_XX records. In that records corresponding to > auxtrace buffers includes: > > 1. PERF_RECORD_AUX > Conveys that new data is available in AUX area > > 2. PERF_RECORD_AUXTRACE_INFO > Describes offset and size of auxtrace data in the buffers > > 3. PERF_RECORD_AUXTRACE > This is the record that defines the auxtrace data which here in case of > vpa-dtl pmu is dispatch trace log data. > > Snippet from perf report -D showing the PERF_RECORD_AUXTRACE dump > > 0 0 0x39b10 [0x30]: PERF_RECORD_AUXTRACE size: 0x690 offset: 0 ref: 0 idx: 0 tid: -1 cpu: 0 > . > . ... VPA DTL PMU data: size 1680 bytes, entries is 35 > . 00000000: boot_tb: 21349649546353231, tb_freq: 512000000 > . 00000030: dispatch_reason:decrementer interrupt, preempt_reason:H_CEDE, enqueue_to_dispatch_time:7064, ready_to_enqueue_time:187, waiting_to_ready_time:6611773 > . 00000060: dispatch_reason:priv doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:146, ready_to_enqueue_time:0, waiting_to_ready_time:15359437 > . 00000090: dispatch_reason:decrementer interrupt, preempt_reason:H_CEDE, enqueue_to_dispatch_time:4868, ready_to_enqueue_time:232, waiting_to_ready_time:5100709 > . 000000c0: dispatch_reason:priv doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:179, ready_to_enqueue_time:0, waiting_to_ready_time:30714243 > . 000000f0: dispatch_reason:priv doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:197, ready_to_enqueue_time:0, waiting_to_ready_time:15350648 > . 00000120: dispatch_reason:priv doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:213, ready_to_enqueue_time:0, waiting_to_ready_time:15353446 > . 00000150: dispatch_reason:priv doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:212, ready_to_enqueue_time:0, waiting_to_ready_time:15355126 > . 00000180: dispatch_reason:decrementer interrupt, preempt_reason:H_CEDE, enqueue_to_dispatch_time:6368, ready_to_enqueue_time:164, waiting_to_ready_time:5104665 > > Above is representation of dtl entry of below format: > > struct dtl_entry { > u8 dispatch_reason; > u8 preempt_reason; > u16 processor_id; > u32 enqueue_to_dispatch_time; > u32 ready_to_enqueue_time; > u32 waiting_to_ready_time; > u64 timebase; > u64 fault_addr; > u64 srr0; > u64 srr1; > }; > > First two fields represent the dispatch reason and preempt reason. The post > procecssing of PERF_RECORD_AUXTRACE records will translate to meaninful data > for user to consume. > > Visualize the dispatch trace log entries with perf report: > # ./perf record -a -e sched:*,vpa_dtl/dtl_all/ -c 1000000000 sleep 1 > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.300 MB perf.data ] > > # ./perf report > # Samples: 321 of event 'vpa-dtl' > # Event count (approx.): 321 > # > # Children Self Command Shared Object Symbol > # ........ ........ ....... ................. .............................. > # > 100.00% 100.00% swapper [kernel.kallsyms] [k] plpar_hcall_norets_notrace > > Visualize the dispatch trace log entries with perf script: > > # ./perf script > perf 13322 [002] 233.835807: sched:sched_switch: perf:13322 [120] R ==> migration/2:27 [0] > migration/2 27 [002] 233.835811: sched:sched_migrate_task: comm=perf pid=13322 prio=120 orig_cpu=2 dest_cpu=3 > migration/2 27 [002] 233.835818: sched:sched_stat_runtime: comm=migration/2 pid=27 runtime=9214 [ns] > migration/2 27 [002] 233.835819: sched:sched_switch: migration/2:27 [0] S ==> swapper/2:0 [120] > swapper 0 [002] 233.835822: vpa-dtl: timebase: 338954486062657 dispatch_reason:decrementer_interrupt, preempt_reason:H_CEDE, enqueue_to_dispatch_time:435, ready_to_enqueue_time:0, waiting_to_ready_time:34775058, processor_id: 202 c0000000000f8094 plpar_hcall_norets_notrace+0x18 ([kernel.kallsyms]) > swapper 0 [001] 233.835886: vpa-dtl: timebase: 338954486095398 dispatch_reason:priv_doorbell, preempt_reason:H_CEDE, enqueue_to_dispatch_time:542, ready_to_enqueue_time:0, waiting_to_ready_time:1245360, processor_id: 201 c0000000000f8094 plpar_hcall_norets_notrace+0x18 ([kernel.kallsyms]) > > Changelog is added for V3 in each individual patch > > Thanks > Athira > > Athira Rajeev (6): > tools/perf: Add basic CONFIG_AUXTRACE support for VPA pmu on powerpc > tools/perf: process auxtrace events and display in perf report -D > tools/perf: Add event name as vpa-dtl of PERF_TYPE_SYNTH type to > present DTL samples > tools/perf: Allocate and setup aux buffer queue to help co-relate with > other events across CPU's > tools/perf: Process the DTL entries in queue and deliver samples > tools/perf: Enable perf script to present the DTL entries > > tools/perf/arch/powerpc/util/Build | 1 + > tools/perf/arch/powerpc/util/auxtrace.c | 103 ++++ > tools/perf/builtin-script.c | 30 + > tools/perf/util/Build | 1 + > tools/perf/util/auxtrace.c | 4 + > tools/perf/util/auxtrace.h | 1 + > tools/perf/util/event.h | 20 + > tools/perf/util/powerpc-vpadtl.c | 734 ++++++++++++++++++++++++ > tools/perf/util/powerpc-vpadtl.h | 23 + > 9 files changed, 917 insertions(+) > create mode 100644 tools/perf/arch/powerpc/util/auxtrace.c > create mode 100644 tools/perf/util/powerpc-vpadtl.c > create mode 100644 tools/perf/util/powerpc-vpadtl.h Hi Athira, I have tested the above patchset on the mainline kernel [ 6.17.0-rc2], it is working fine. Please add the tag below, for the entire series. Tested-by: Tejas Manhas Thanks & Regards, Tejas >