diff options
| author | KAMEZAWA Hiroyuki <[email protected]> | 2010-10-27 15:34:13 -0700 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2010-10-27 18:03:13 -0700 |
| commit | f2c66cd8eeddedb440f33bc0f5cec1ed7ae376cb (patch) | |
| tree | 4b8cfcd2a76652839121707fc2a49b70489ec055 /tools/perf/scripts/python/bin | |
| parent | 19cd56c48da58bebc3a638e036bcab69469acd27 (diff) | |
/proc/stat: scalability of irq num per cpu
/proc/stat shows the total number of all interrupts to each cpu. But when
the number of IRQs are very large, it take very long time and 'cat
/proc/stat' takes more than 10 secs. This is because sum of all irq
events are counted when /proc/stat is read. This patch adds "sum of all
irq" counter percpu and reduce read costs.
The cost of reading /proc/stat is important because it's used by major
applications as 'top', 'ps', 'w', etc....
A test on a mechin (4096cpu, 256 nodes, 4592 irqs) shows
%time cat /proc/stat > /dev/null
Before Patch: 12.627 sec
After Patch: 2.459 sec
Signed-off-by: KAMEZAWA Hiroyuki <[email protected]>
Tested-by: Jack Steiner <[email protected]>
Acked-by: Jack Steiner <[email protected]>
Cc: Yinghai Lu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Diffstat (limited to 'tools/perf/scripts/python/bin')
0 files changed, 0 insertions, 0 deletions