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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1733496536; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nus0pwrOAvj296nGbcki0OxsA+YK0oIFFlKunpHROQo=; b=4+EyLU4AveH90bygPoPUlEU/Ps2mxGejET4ROGABnPAaO3fnQxMPbYHdOuWxnUIjsPJ7um l/kOTH1iEEvES6NSHrjgPAwyVndH2sCxh+Y6J6OQtEXC5WQes5/FGt+SFpYel8TIPLWpea CF5hBgDkie5OH+W1/ZT4h98CE/YTSRA= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 86370A442C9; Fri, 6 Dec 2024 14:47:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12C29C4CED1; Fri, 6 Dec 2024 14:49:07 +0000 (UTC) Date: Fri, 6 Dec 2024 09:49:15 -0500 From: Steven Rostedt To: Raghavendra K T Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, gourry@gourry.net, nehagholkar@meta.com, abhishekd@meta.com, david@redhat.com, ying.huang@intel.com, nphamcs@gmail.com, akpm@linux-foundation.org, hannes@cmpxchg.org, feng.tang@intel.com, kbusch@meta.com, bharata@amd.com, Hasan.Maruf@amd.com, sj@kernel.org, willy@infradead.org, kirill.shutemov@linux.intel.com, mgorman@techsingularity.net, vbabka@suse.cz, hughd@google.com, rientjes@google.com, shy828301@gmail.com, Liam.Howlett@Oracle.com, peterz@infradead.org, mingo@redhat.com, Masami Hiramatsu , linux-trace-kernel@vger.kernel.org Subject: Re: [RFC PATCH V0 09/10] trace/kmmscand: Add tracing of scanning and migration Message-ID: <20241206094915.7d198a3f@gandalf.local.home> In-Reply-To: <86d39d52-fcc0-4215-8b68-ea6e526c0a01@amd.com> References: <20241201153818.2633616-1-raghavendra.kt@amd.com> <20241201153818.2633616-10-raghavendra.kt@amd.com> <20241205124645.0d56ea57@gandalf.local.home> <86d39d52-fcc0-4215-8b68-ea6e526c0a01@amd.com> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: fagk4ocyc69c1ck579idxy4uqxcrwwhi X-Rspam-User: X-Rspamd-Queue-Id: 1D9121C0007 X-Rspamd-Server: rspam08 X-HE-Tag: 1733496519-977459 X-HE-Meta: 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 qfqL0DiK rW0W4D4sZavhFrjHTSjmOqtk+BSHxeSH2r3QrE+5ThWmfkvshofZtmmTB2APR02LZo768uhlxYPVU3rpGubjKQMjV0WoGfaXL5pb0bJ645obwJ25f0/fNnfaSg+1vGpXTRR5E4E10YieCdUgwVgQgFW1S00/p4rIxaYd2Y4R0PhaiWbP+N9ZqHrLnB8qG0ax9DEDz8XXS60wENvicVGxxyxGNX625QXXJjkKxY3NLPkP5T1LLoFDiBDhNi0qEV64XA6q5k55ecD1v1jiFJ8ldVHyQ47DLMPEl3oB+DXMRa1X3rYHVVvCe8PR4Z6l8iY+/JVV+QDKYRpXiRPnIB/JfM5uMGekWiRvcorhfI4gl/PRzmos= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 6 Dec 2024 12:03:29 +0530 Raghavendra K T wrote: > On 12/5/2024 11:16 PM, Steven Rostedt wrote: > > On Sun, 1 Dec 2024 15:38:17 +0000 > > Raghavendra K T wrote: > > > >> Add tracing support to track > >> - start and end of scanning. > >> - migration. > >> > >> CC: Steven Rostedt > >> CC: Masami Hiramatsu > >> CC: linux-trace-kernel@vger.kernel.org > >> > > [...] > > >> + > >> + TP_STRUCT__entry( > >> + __array( char, comm, TASK_COMM_LEN ) > > > > Is there a reason to record "comm"? There's other ways to retrieve it than > > to always write it to the ring buffer. > > > > Thank you for the review Steve. The motivation was to filter benchmark > in the trace to understand the behavior. > I will explore regarding other ways of retrieving comm. > (or may be even PID is enough..) You can filter on current comm for any event with trace-cmd and even with the "filter" file. It doesn't need to be part of the event. For the filter file: # echo "COMM == rcu_preempt" > /sys/kernel/tracing/events/timer/hrtimer_cancel/filter or with trace-cmd # trace-cmd start -e hrtimer_cancel -f 'COMM == "rcu_preempt"' # trace-cmd show # tracer: nop # # entries-in-buffer/entries-written: 10/10 #P:8 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | rcu_preempt-18 [001] d..3. 54968.170887: hrtimer_cancel: hrtimer=00000000456b5702 rcu_preempt-18 [001] d..3. 54968.177704: hrtimer_cancel: hrtimer=00000000456b5702 rcu_preempt-18 [001] d..3. 54968.181678: hrtimer_cancel: hrtimer=00000000456b5702 rcu_preempt-18 [001] d..3. 54968.185679: hrtimer_cancel: hrtimer=00000000456b5702 rcu_preempt-18 [001] d..3. 54968.186092: hrtimer_cancel: hrtimer=00000000456b5702 rcu_preempt-18 [001] d..3. 54968.193676: hrtimer_cancel: hrtimer=00000000456b5702 rcu_preempt-18 [001] d..3. 54968.193686: hrtimer_cancel: hrtimer=00000000456b5702 rcu_preempt-18 [001] d..3. 54972.871315: hrtimer_cancel: hrtimer=00000000456b5702 rcu_preempt-18 [001] d..3. 54972.875176: hrtimer_cancel: hrtimer=00000000456b5702 rcu_preempt-18 [001] d..3. 54972.881751: hrtimer_cancel: hrtimer=00000000456b5702 Or you can do it after the fact from a trace.dat file: # trace-cmd record -e hrtimer_cancel sleep 10 # trace-cmd report | head cpus=8 sleep-1641 [006] d.h2. 55109.598846: hrtimer_cancel: hrtimer=0xffff9800fdfa1888 sleep-1641 [006] d..3. 55109.599089: hrtimer_cancel: hrtimer=0xffff9800fdfb3140 -0 [006] d..2. 55109.599111: hrtimer_cancel: hrtimer=0xffff9800fdfa1888 -0 [006] d.h7. 55109.603848: hrtimer_cancel: hrtimer=0xffff9800fdfb3180 -0 [006] dN.2. 55109.603895: hrtimer_cancel: hrtimer=0xffff9800fdfa1888 -0 [000] d.h3. 55109.604478: hrtimer_cancel: hrtimer=0xffff9800fde33180 -0 [000] dN.2. 55109.604492: hrtimer_cancel: hrtimer=0xffff9800fde21888 rcu_preempt-18 [000] d..3. 55109.604549: hrtimer_cancel: hrtimer=0xffff9800fde33140 -0 [000] d..2. 55109.604573: hrtimer_cancel: hrtimer=0xffff9800fde21888 # trace-cmd report -F '.*:COMM == "rcu_preempt"' cpus=8 rcu_preempt-18 [000] d..3. 55109.604549: hrtimer_cancel: hrtimer=0xffff9800fde33140 rcu_preempt-18 [000] d..3. 55109.609320: hrtimer_cancel: hrtimer=0xffff9800fde33140 rcu_preempt-18 [000] d..3. 55109.613350: hrtimer_cancel: hrtimer=0xffff9800fde33140 rcu_preempt-18 [000] d..3. 55119.609772: hrtimer_cancel: hrtimer=0xffff9800fde33140 -- Steve