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>
diff --git a/fs/proc/array.c b/fs/proc/array.c
index c602b8d..fbb53c2 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -462,59 +462,56 @@
/* convert nsec -> ticks */
start_time = nsec_to_clock_t(start_time);
- seq_printf(m, "%d (%s) %c %d %d %d %d %d %u %lu \
-%lu %lu %lu %lu %lu %ld %ld %ld %ld %d 0 %llu %lu %ld %lu %lu %lu %lu %lu \
-%lu %lu %lu %lu %lu %lu %lu %lu %d %d %u %u %llu %lu %ld %lu %lu %lu\n",
- pid_nr_ns(pid, ns),
- tcomm,
- state,
- ppid,
- pgid,
- sid,
- tty_nr,
- tty_pgrp,
- task->flags,
- min_flt,
- cmin_flt,
- maj_flt,
- cmaj_flt,
- cputime_to_clock_t(utime),
- cputime_to_clock_t(stime),
- cputime_to_clock_t(cutime),
- cputime_to_clock_t(cstime),
- priority,
- nice,
- num_threads,
- start_time,
- vsize,
- mm ? get_mm_rss(mm) : 0,
- rsslim,
- mm ? (permitted ? mm->start_code : 1) : 0,
- mm ? (permitted ? mm->end_code : 1) : 0,
- (permitted && mm) ? mm->start_stack : 0,
- esp,
- eip,
- /* The signal information here is obsolete.
- * It must be decimal for Linux 2.0 compatibility.
- * Use /proc/#/status for real-time signals.
- */
- task->pending.signal.sig[0] & 0x7fffffffUL,
- task->blocked.sig[0] & 0x7fffffffUL,
- sigign .sig[0] & 0x7fffffffUL,
- sigcatch .sig[0] & 0x7fffffffUL,
- wchan,
- 0UL,
- 0UL,
- task->exit_signal,
- task_cpu(task),
- task->rt_priority,
- task->policy,
- (unsigned long long)delayacct_blkio_ticks(task),
- cputime_to_clock_t(gtime),
- cputime_to_clock_t(cgtime),
- (mm && permitted) ? mm->start_data : 0,
- (mm && permitted) ? mm->end_data : 0,
- (mm && permitted) ? mm->start_brk : 0);
+ seq_printf(m, "%d (%s) %c", pid_nr_ns(pid, ns), tcomm, state);
+ seq_put_decimal_ll(m, ' ', ppid);
+ seq_put_decimal_ll(m, ' ', pgid);
+ seq_put_decimal_ll(m, ' ', sid);
+ seq_put_decimal_ll(m, ' ', tty_nr);
+ seq_put_decimal_ll(m, ' ', tty_pgrp);
+ seq_put_decimal_ull(m, ' ', task->flags);
+ seq_put_decimal_ull(m, ' ', min_flt);
+ seq_put_decimal_ull(m, ' ', cmin_flt);
+ seq_put_decimal_ull(m, ' ', maj_flt);
+ seq_put_decimal_ull(m, ' ', cmaj_flt);
+ seq_put_decimal_ull(m, ' ', cputime_to_clock_t(utime));
+ seq_put_decimal_ull(m, ' ', cputime_to_clock_t(stime));
+ seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cutime));
+ seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cstime));
+ seq_put_decimal_ll(m, ' ', priority);
+ seq_put_decimal_ll(m, ' ', nice);
+ seq_put_decimal_ll(m, ' ', num_threads);
+ seq_put_decimal_ull(m, ' ', 0);
+ seq_put_decimal_ull(m, ' ', start_time);
+ seq_put_decimal_ull(m, ' ', vsize);
+ seq_put_decimal_ll(m, ' ', mm ? get_mm_rss(mm) : 0);
+ seq_put_decimal_ull(m, ' ', rsslim);
+ seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->start_code : 1) : 0);
+ seq_put_decimal_ull(m, ' ', mm ? (permitted ? mm->end_code : 1) : 0);
+ seq_put_decimal_ull(m, ' ', (permitted && mm) ? mm->start_stack : 0);
+ seq_put_decimal_ull(m, ' ', esp);
+ seq_put_decimal_ull(m, ' ', eip);
+ /* The signal information here is obsolete.
+ * It must be decimal for Linux 2.0 compatibility.
+ * Use /proc/#/status for real-time signals.
+ */
+ seq_put_decimal_ull(m, ' ', task->pending.signal.sig[0] & 0x7fffffffUL);
+ seq_put_decimal_ull(m, ' ', task->blocked.sig[0] & 0x7fffffffUL);
+ seq_put_decimal_ull(m, ' ', sigign.sig[0] & 0x7fffffffUL);
+ seq_put_decimal_ull(m, ' ', sigcatch.sig[0] & 0x7fffffffUL);
+ seq_put_decimal_ull(m, ' ', wchan);
+ seq_put_decimal_ull(m, ' ', 0);
+ seq_put_decimal_ull(m, ' ', 0);
+ seq_put_decimal_ll(m, ' ', task->exit_signal);
+ seq_put_decimal_ll(m, ' ', task_cpu(task));
+ seq_put_decimal_ull(m, ' ', task->rt_priority);
+ seq_put_decimal_ull(m, ' ', task->policy);
+ seq_put_decimal_ull(m, ' ', delayacct_blkio_ticks(task));
+ seq_put_decimal_ull(m, ' ', cputime_to_clock_t(gtime));
+ seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cgtime));
+ seq_put_decimal_ull(m, ' ', (mm && permitted) ? mm->start_data : 0);
+ seq_put_decimal_ull(m, ' ', (mm && permitted) ? mm->end_data : 0);
+ seq_put_decimal_ull(m, ' ', (mm && permitted) ? mm->start_brk : 0);
+ seq_putc(m, '\n');
if (mm)
mmput(mm);
return 0;
@@ -542,8 +539,20 @@
size = task_statm(mm, &shared, &text, &data, &resident);
mmput(mm);
}
- seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
- size, resident, shared, text, data);
+ /*
+ * For quick read, open code by putting numbers directly
+ * expected format is
+ * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
+ * size, resident, shared, text, data);
+ */
+ seq_put_decimal_ull(m, 0, size);
+ seq_put_decimal_ull(m, ' ', resident);
+ seq_put_decimal_ull(m, ' ', shared);
+ seq_put_decimal_ull(m, ' ', text);
+ seq_put_decimal_ull(m, ' ', 0);
+ seq_put_decimal_ull(m, ' ', text);
+ seq_put_decimal_ull(m, ' ', 0);
+ seq_putc(m, '\n');
return 0;
}