From: Kajol Jain <kjain@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au
Cc: nathanl@linux.ibm.com, ego@linux.vnet.ibm.com,
maddy@linux.vnet.ibm.com, kjain@linux.ibm.com, suka@us.ibm.com,
anju@linux.vnet.ibm.com
Subject: [PATCH v4 0/2] Add cpu hotplug support for powerpc/perf/hv-24x7
Date: Wed, 8 Jul 2020 14:29:53 +0530 [thread overview]
Message-ID: <20200708085955.655686-1-kjain@linux.ibm.com> (raw)
This patchset add cpu hotplug support for hv_24x7 driver by adding
online/offline cpu hotplug function. It also add sysfs file
"cpumask" to expose current online cpu that can be used for
hv_24x7 event count.
Changelog:
v3 -> v4
- Make PMU initialization fail incase hotplug init failed. Rather then
just printing error msg.
- Did some nits changes like removing extra comment and initialising
target value part as suggested by Michael Ellerman
- Retained Reviewd-by tag because the changes were fixes to some nits.
- Incase we sequentially offline multiple cpus, taking cpumask_first() may
add some latency in that scenario.
So, I was trying to test benchmark in power9 lpar with 16 cpu,
by off-lining cpu 0-14
With cpumask_last: This is what I got.
real 0m2.812s
user 0m0.002s
sys 0m0.003s
With cpulast_any:
real 0m3.690s
user 0m0.002s
sys 0m0.062s
That's why I just went with cpumask_last thing.
v2 -> v3
- Corrected some of the typo mistakes and update commit message
as suggested by Gautham R Shenoy.
- Added Reviewed-by tag for the first patch in the patchset.
v1 -> v2
- Changed function to pick active cpu incase of offline
from "cpumask_any_but" to "cpumask_last", as
cpumask_any_but function pick very next online cpu and incase where
we are sequentially off-lining multiple cpus, "pmu_migrate_context"
can add extra latency.
- Suggested by: Gautham R Shenoy.
- Change documentation for cpumask and rather then hardcode the
initialization for cpumask_attr_group, add loop to get very first
NULL as suggested by Gautham R Shenoy.
Kajol Jain (2):
powerpc/perf/hv-24x7: Add cpu hotplug support
powerpc/hv-24x7: Add sysfs files inside hv-24x7 device to show cpumask
.../sysfs-bus-event_source-devices-hv_24x7 | 7 ++
arch/powerpc/perf/hv-24x7.c | 79 ++++++++++++++++++-
include/linux/cpuhotplug.h | 1 +
3 files changed, 86 insertions(+), 1 deletion(-)
--
2.26.2
next reply other threads:[~2020-07-08 9:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-08 8:59 Kajol Jain [this message]
2020-07-08 8:59 ` [PATCH v4 1/2] powerpc/perf/hv-24x7: Add cpu hotplug support Kajol Jain
2020-07-08 8:59 ` [PATCH v4 2/2] powerpc/hv-24x7: Add sysfs files inside hv-24x7 device to show cpumask Kajol Jain
2020-07-08 9:34 ` Madhavan Srinivasan
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