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proc: del loop sscanf for proc pid stat file

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Loop sscanf and strtok will take a long cpu time, since
get_proc_stat is called per thread. So, replace these with a single sscanf,
which will save much cpu time.
Signed-off-by: nocjj <1250062498@qq.com>
This commit is contained in:
Huawei Technologies Co., Ltd 2021-03-16 16:23:23 +08:00 committed by Alex Chen
parent 13badcdda8
commit 6c00a8de63
1 changed files with 129 additions and 0 deletions
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129
proc-del-loop-sscanf-for-proc-pid-stat-file.patch Normal file
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@ -0,0 +1,129 @@
From 3afac4c6992006c31fa33fe351bf27eedc34be1c Mon Sep 17 00:00:00 2001
From: nocjj <1250062498@qq.com>
Date: Tue, 16 Mar 2021 16:23:23 +0800
Subject: [PATCH] proc: del loop sscanf for proc pid stat file
Loop sscanf and strtok will take a long cpu time, since
get_proc_stat is called per thread. So, replace these with a single sscanf,
which will save much cpu time.
Signed-off-by: nocjj <1250062498@qq.com>
---
src/proc.c | 73 +++++++++++++++++-------------------------------------
src/type.h | 2 +-
2 files changed, 24 insertions(+), 51 deletions(-)
diff --git a/src/proc.c b/src/proc.c
index d33ede3..a722a92 100644
--- a/src/proc.c
+++ b/src/proc.c
@@ -19,46 +19,9 @@
#define STAT_PATH_SIZE 40
struct file_item proc_stab[] = {
-#define GDF(f) (void *)GET_NAME(f), (void *)DELTA_NAME(f), NULL
-#define GF(f) (void *)GET_NAME(f), NULL, NULL
- {"%c", GF(state)},
- {"%d", GF(ppid)},
- {"%d", GF(pgrd)},
- {"%*d", NULL, NULL, NULL},
- {"%*d", NULL, NULL, NULL},
- {"%*d", NULL, NULL, NULL},
- {"%lu", GF(flags)},
- {"%lu", GF(min_flt)},
- {"%lu", GF(cmin_flt)},
- {"%lu", GF(maj_flt)},
- {"%lu", GF(cmaj_flt)},
+#define GDF(f) NULL, (void *)DELTA_NAME(f), NULL
{"%llu", GDF(utime)},
- {"%llu", GDF(stime)},
- {"%llu", GF(cutime)},
- {"%llu", GF(cstime)},
- {"%*ld", NULL, NULL, NULL},
- {"%*ld", NULL, NULL, NULL},
- {"%d", GF(nlwp)},
- {"%ld", GF(alarm)},
- {"%llu", GF(start_time)},
- {"%lu", GF(vsize)},
- {"%ld", GF(rss)},
- {"%lu", GF(rss_rlim)},
- {"%*lu", NULL, NULL, NULL},
- {"%*lu", NULL, NULL, NULL},
- {"%*lu", NULL, NULL, NULL},
- {"%*lu", NULL, NULL, NULL},
- {"%*lu", NULL, NULL, NULL},
- {"%*s", NULL, NULL, NULL}, /* discard signal */
- {"%*s", NULL, NULL, NULL}, /* discard blocked */
- {"%*s", NULL, NULL, NULL}, /* discard sigignore */
- {"%*s", NULL, NULL, NULL}, /* discard sigcatch */
- {"%*lu", NULL, NULL, NULL},
- {"%*u", NULL, NULL, NULL}, /* dsicard nswap */
- {"%*u", NULL, NULL, NULL}, /* discard cnswap */
- {"%*d", NULL, NULL, NULL},
- {"%d", GF(processor)}
-#undef GF
+ {"%llu", GDF(stime)}
#undef GDF
};
@@ -70,9 +33,6 @@ int get_proc_stat(struct domain *dom)
char path[STAT_PATH_SIZE];
char *tmp1 = NULL;
char *tmp2 = NULL;
- char *p = NULL;
- char *p_next = NULL;
- int i = 0;
int len;
if (dom->type == ISDOMAIN) {
@@ -100,14 +60,27 @@ int get_proc_stat(struct domain *dom)
dom->vmname[len] = '\0';
/* read start from process state */
- tmp2 = tmp2 + 2;
- for (p = strtok_r(tmp2, " \t\r\n", &p_next); p && i < stat_size;
- p = strtok_r(NULL, " \t\r\n", &p_next)) {
- if (proc_stab[i].get_fun != NULL) {
- sscanf(p, proc_stab[i].format, (*proc_stab[i].get_fun)(dom));
- }
- ++i;
- }
+ sscanf(tmp2 + 2,
+ "%c "
+ "%d %d %*d %*d %*d "
+ "%lu "
+ "%lu %lu %lu %lu "
+ "%llu %llu %llu %llu "
+ "%*d %*d "
+ "%d %ld "
+ "%llu %lu %ld %lu "
+ "%*u %*u %*u %*u %*u "
+ "%*s %*s %*s %*s "
+ "%*u %*u %*u %*d "
+ "%d",
+ &(dom->state),
+ &(dom->ppid), &(dom->pgrd),
+ &(dom->flags),
+ &(dom->min_flt), &(dom->cmin_flt), &(dom->maj_flt), &(dom->cmaj_flt),
+ &(dom->utime), &(dom->stime), &(dom->cutime), &(dom->cstime),
+ &(dom->nlwp), &(dom->alarm),
+ &(dom->start_time), &(dom->vsize), &(dom->rss), &(dom->rss_rlim),
+ &(dom->processor));
return 1;
}
diff --git a/src/type.h b/src/type.h
index f5d148c..77dd696 100644
--- a/src/type.h
+++ b/src/type.h
@@ -86,7 +86,7 @@ struct domain {
long int
alarm,
rss;
- unsigned int
+ unsigned long
flags,
min_flt,
cmin_flt,
--
2.27.0