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* [PATCH 0/2] /proc/stat: Reduce irqs counting performance overhead
@ 2019-01-07 15:12 Waiman Long
  2019-01-07 15:12 ` [PATCH 1/2] /proc/stat: Extract irqs counting code into show_stat_irqs() Waiman Long
                   ` (2 more replies)
  0 siblings, 3 replies; 23+ messages in thread
From: Waiman Long @ 2019-01-07 15:12 UTC (permalink / raw)
  To: Andrew Morton, Alexey Dobriyan, Luis Chamberlain, Kees Cook,
	Jonathan Corbet
  Cc: linux-kernel, linux-doc, linux-fsdevel, Davidlohr Bueso,
	Miklos Szeredi, Daniel Colascione, Dave Chinner, Randy Dunlap,
	Waiman Long

As newer systems have more and more IRQs and CPUs available in their
system, the performance of reading /proc/stat frequently is getting
worse and worse.

Last year, I had proposed patch to extract out the IRQ line of /proc/stat
into a new procfs file. However, this may break existing applications
that depend on the presence of the IRQ line in /proc/stat.

Davidlohr had proposed a new /proc/stat2 file which is almost the same
as /proc/stat except that it has no IRQ line. This will require change
in applications to use the new procfs file.

This patchset uses a different approach to reduce the performance impact
by using a sysctl parameter to control the maximum frequency at which the
IRQ count computation can be done. The result is that the IRQ counts from
/proc/stat may be a bit stale, but still provide the needed information.

Waiman Long (2):
  /proc/stat: Extract irqs counting code into show_stat_irqs()
  /proc/stat: Add sysctl parameter to control irq counts latency

 Documentation/sysctl/fs.txt | 16 +++++++++
 fs/proc/stat.c              | 87 +++++++++++++++++++++++++++++++++++++++------
 kernel/sysctl.c             | 12 +++++++
 3 files changed, 105 insertions(+), 10 deletions(-)

-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

end of thread, other threads:[~2019-01-21 21:25 UTC | newest]

Thread overview: 23+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-01-07 15:12 [PATCH 0/2] /proc/stat: Reduce irqs counting performance overhead Waiman Long
2019-01-07 15:12 ` [PATCH 1/2] /proc/stat: Extract irqs counting code into show_stat_irqs() Waiman Long
2019-01-07 21:42   ` Kees Cook
2019-01-07 15:12 ` [PATCH 2/2] /proc/stat: Add sysctl parameter to control irq counts latency Waiman Long
2019-01-07 15:58   ` Matthew Wilcox
2019-01-07 16:07     ` Waiman Long
2019-01-07 16:14       ` Matthew Wilcox
2019-01-07 16:19         ` Waiman Long
2019-01-07 16:33     ` Alexey Dobriyan
2019-01-07 16:59       ` Waiman Long
2019-01-18  8:44   ` [LKP] [/proc/stat] 3047027b34: reaim.jobs_per_min -4.8% regression kernel test robot
2019-01-21 20:02     ` Kees Cook
2019-01-21 21:25       ` Alexey Dobriyan
2019-01-07 22:32 ` [PATCH 0/2] /proc/stat: Reduce irqs counting performance overhead Dave Chinner
2019-01-07 22:41   ` Daniel Colascione
2019-01-07 23:49     ` Alexey Dobriyan
2019-01-07 22:41   ` Waiman Long
2019-01-08  2:04     ` Dave Chinner
2019-01-08 16:11       ` Michal Hocko
2019-01-08 17:05         ` Waiman Long
2019-01-08 17:32           ` Waiman Long
2019-01-08 16:58       ` Waiman Long
2019-01-08 22:27         ` Dave Chinner

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