From: Steven Rostedt <rostedt@goodmis.org>
To: Raghavendra K T <raghavendra.kt@amd.com>
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 <mhiramat@kernel.org>,
linux-trace-kernel@vger.kernel.org
Subject: Re: [RFC PATCH V0 09/10] trace/kmmscand: Add tracing of scanning and migration
Date: Fri, 6 Dec 2024 09:49:15 -0500 [thread overview]
Message-ID: <20241206094915.7d198a3f@gandalf.local.home> (raw)
In-Reply-To: <86d39d52-fcc0-4215-8b68-ea6e526c0a01@amd.com>
On Fri, 6 Dec 2024 12:03:29 +0530
Raghavendra K T <raghavendra.kt@amd.com> wrote:
> On 12/5/2024 11:16 PM, Steven Rostedt wrote:
> > On Sun, 1 Dec 2024 15:38:17 +0000
> > Raghavendra K T <raghavendra.kt@amd.com> wrote:
> >
> >> Add tracing support to track
> >> - start and end of scanning.
> >> - migration.
> >>
> >> CC: Steven Rostedt <rostedt@goodmis.org>
> >> CC: Masami Hiramatsu <mhiramat@kernel.org>
> >> 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
<idle>-0 [006] d..2. 55109.599111: hrtimer_cancel: hrtimer=0xffff9800fdfa1888
<idle>-0 [006] d.h7. 55109.603848: hrtimer_cancel: hrtimer=0xffff9800fdfb3180
<idle>-0 [006] dN.2. 55109.603895: hrtimer_cancel: hrtimer=0xffff9800fdfa1888
<idle>-0 [000] d.h3. 55109.604478: hrtimer_cancel: hrtimer=0xffff9800fde33180
<idle>-0 [000] dN.2. 55109.604492: hrtimer_cancel: hrtimer=0xffff9800fde21888
rcu_preempt-18 [000] d..3. 55109.604549: hrtimer_cancel: hrtimer=0xffff9800fde33140
<idle>-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
next prev parent reply other threads:[~2024-12-06 14:49 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-01 15:38 [RFC PATCH V0 0/10] mm: slowtier page promotion based on PTE A bit Raghavendra K T
2024-12-01 15:38 ` [RFC PATCH V0 01/10] mm: Add kmmscand kernel daemon Raghavendra K T
2024-12-01 15:38 ` [RFC PATCH V0 02/10] mm: Maintain mm_struct list in the system Raghavendra K T
2024-12-01 15:38 ` [RFC PATCH V0 03/10] mm: Scan the mm and create a migration list Raghavendra K T
2024-12-01 15:38 ` [RFC PATCH V0 04/10] mm/migration: Migrate accessed folios to toptier node Raghavendra K T
2024-12-01 15:38 ` [RFC PATCH V0 05/10] mm: Add throttling of mm scanning using scan_period Raghavendra K T
2024-12-01 15:38 ` [RFC PATCH V0 06/10] mm: Add throttling of mm scanning using scan_size Raghavendra K T
2024-12-01 15:38 ` [RFC PATCH V0 07/10] sysfs: Add sysfs support to tune scanning Raghavendra K T
2024-12-01 15:38 ` [RFC PATCH V0 08/10] vmstat: Add vmstat counters Raghavendra K T
2024-12-01 15:38 ` [RFC PATCH V0 09/10] trace/kmmscand: Add tracing of scanning and migration Raghavendra K T
2024-12-05 17:46 ` Steven Rostedt
2024-12-06 6:33 ` Raghavendra K T
2024-12-06 14:49 ` Steven Rostedt [this message]
2024-12-01 15:38 ` [RFC PATCH V0 DO NOT MERGE 10/10] kmmscand: Add scanning Raghavendra K T
2024-12-10 18:53 ` [RFC PATCH V0 0/10] mm: slowtier page promotion based on PTE A bit SeongJae Park
2024-12-20 6:30 ` Raghavendra K T
2025-02-12 17:02 ` Davidlohr Bueso
2025-02-13 5:39 ` Raghavendra K T
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