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| author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2012-03-23 15:02:54 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-23 16:58:42 -0700 |
| commit | bda7bad62bc4c4e0783348e8db51abe094153c56 (patch) | |
| tree | c62650a3da656ba18aebe170df7d554158ae5fc5 /include/linux/seq_file.h | |
| parent | 1ac101a5d675aca2426c5cd460c73fb95acb8391 (diff) | |
| download | linux-bda7bad62bc4c4e0783348e8db51abe094153c56.tar.gz | |
procfs: speed up /proc/pid/stat, statm
Process accounting applications as top, ps visit some files under
/proc/<pid>. With seq_put_decimal_ull(), we can optimize /proc/<pid>/stat
and /proc/<pid>/statm files.
This patch adds
- seq_put_decimal_ll() for signed values.
- allow delimiter == 0.
- convert seq_printf() to seq_put_decimal_ull/ll in /proc/stat, statm.
Test result on a system with 2000+ procs.
Before patch:
[kamezawa@bluextal test]$ top -b -n 1 | wc -l
2223
[kamezawa@bluextal test]$ time top -b -n 1 > /dev/null
real 0m0.675s
user 0m0.044s
sys 0m0.121s
[kamezawa@bluextal test]$ time ps -elf > /dev/null
real 0m0.236s
user 0m0.056s
sys 0m0.176s
After patch:
kamezawa@bluextal ~]$ time top -b -n 1 > /dev/null
real 0m0.657s
user 0m0.052s
sys 0m0.100s
[kamezawa@bluextal ~]$ time ps -elf > /dev/null
real 0m0.198s
user 0m0.050s
sys 0m0.145s
Considering top, ps tend to scan /proc periodically, this will reduce cpu
consumption by top/ps to some extent.
[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/seq_file.h')
| -rw-r--r-- | include/linux/seq_file.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h index 5bba42c99448..54e5ae7f8adc 100644 --- a/include/linux/seq_file.h +++ b/include/linux/seq_file.h @@ -123,6 +123,8 @@ int seq_open_private(struct file *, const struct seq_operations *, int); int seq_release_private(struct inode *, struct file *); int seq_put_decimal_ull(struct seq_file *m, char delimiter, unsigned long long num); +int seq_put_decimal_ll(struct seq_file *m, char delimiter, + long long num); #define SEQ_START_TOKEN ((void *)1) /* |