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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2012-03-24 02:02:54 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-24 03:58:42 +0400
commitbda7bad62bc4c4e0783348e8db51abe094153c56 (patch)
treec62650a3da656ba18aebe170df7d554158ae5fc5 /include
parent1ac101a5d675aca2426c5cd460c73fb95acb8391 (diff)
downloadlinux-bda7bad62bc4c4e0783348e8db51abe094153c56.tar.xz
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')
-rw-r--r--include/linux/seq_file.h2
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)
/*