taskstats: add context-switch counters

Make available to the user the following task and process performance
statistics:

	* Involuntary Context Switches (task_struct->nivcsw)
	* Voluntary Context Switches (task_struct->nvcsw)

Statistics information is available from:
	1. taskstats interface (Documentation/accounting/)
	2. /proc/PID/status (task only).

This data is useful for detecting hyperactivity patterns between processes.

[akpm@linux-foundation.org: cleanup]
Signed-off-by: Maxim Uvarov <muvarov@ru.mvista.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Jonathan Lim <jlim@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Maxim Uvarov 2007-07-15 23:40:48 -07:00 committed by Linus Torvalds
parent a6c15c2b0f
commit b663a79c19
5 changed files with 41 additions and 3 deletions

View file

@ -49,6 +49,7 @@ char name[100];
int dbg;
int print_delays;
int print_io_accounting;
int print_task_context_switch_counts;
__u64 stime, utime;
#define PRINTF(fmt, arg...) { \
@ -195,7 +196,7 @@ void print_delayacct(struct taskstats *t)
"IO %15s%15s\n"
" %15llu%15llu\n"
"MEM %15s%15s\n"
" %15llu%15llu\n\n",
" %15llu%15llu\n"
"count", "real total", "virtual total", "delay total",
t->cpu_count, t->cpu_run_real_total, t->cpu_run_virtual_total,
t->cpu_delay_total,
@ -204,6 +205,14 @@ void print_delayacct(struct taskstats *t)
"count", "delay total", t->swapin_count, t->swapin_delay_total);
}
void task_context_switch_counts(struct taskstats *t)
{
printf("\n\nTask %15s%15s\n"
" %15lu%15lu\n",
"voluntary", "nonvoluntary",
t->nvcsw, t->nivcsw);
}
void print_ioacct(struct taskstats *t)
{
printf("%s: read=%llu, write=%llu, cancelled_write=%llu\n",
@ -235,7 +244,7 @@ int main(int argc, char *argv[])
struct msgtemplate msg;
while (1) {
c = getopt(argc, argv, "diw:r:m:t:p:vl");
c = getopt(argc, argv, "qdiw:r:m:t:p:vl");
if (c < 0)
break;
@ -248,6 +257,10 @@ int main(int argc, char *argv[])
printf("printing IO accounting\n");
print_io_accounting = 1;
break;
case 'q':
printf("printing task/process context switch rates\n");
print_task_context_switch_counts = 1;
break;
case 'w':
logfile = strdup(optarg);
printf("write to file %s\n", logfile);
@ -389,6 +402,8 @@ int main(int argc, char *argv[])
print_delayacct((struct taskstats *) NLA_DATA(na));
if (print_io_accounting)
print_ioacct((struct taskstats *) NLA_DATA(na));
if (print_task_context_switch_counts)
task_context_switch_counts((struct taskstats *) NLA_DATA(na));
if (fd) {
if (write(fd, NLA_DATA(na), na->nla_len) < 0) {
err(1,"write error\n");

View file

@ -22,6 +22,8 @@ There are three different groups of fields in the struct taskstats:
/* Extended accounting fields end */
Their values are collected if CONFIG_TASK_XACCT is set.
4) Per-task and per-thread context switch count statistics
Future extension should add fields to the end of the taskstats struct, and
should not change the relative position of each field within the struct.
@ -158,4 +160,8 @@ struct taskstats {
/* Extended accounting fields end */
4) Per-task and per-thread statistics
__u64 nvcsw; /* Context voluntary switch counter */
__u64 nivcsw; /* Context involuntary switch counter */
}

View file

@ -289,6 +289,15 @@ static inline char *task_cap(struct task_struct *p, char *buffer)
cap_t(p->cap_effective));
}
static inline char *task_context_switch_counts(struct task_struct *p,
char *buffer)
{
return buffer + sprintf(buffer, "voluntary_ctxt_switches:\t%lu\n"
"nonvoluntary_ctxt_switches:\t%lu\n",
p->nvcsw,
p->nivcsw);
}
int proc_pid_status(struct task_struct *task, char * buffer)
{
char * orig = buffer;
@ -307,6 +316,7 @@ int proc_pid_status(struct task_struct *task, char * buffer)
#if defined(CONFIG_S390)
buffer = task_show_regs(task, buffer);
#endif
buffer = task_context_switch_counts(task, buffer);
return buffer - orig;
}

View file

@ -31,7 +31,7 @@
*/
#define TASKSTATS_VERSION 4
#define TASKSTATS_VERSION 5
#define TS_COMM_LEN 32 /* should be >= TASK_COMM_LEN
* in linux/sched.h */
@ -149,6 +149,9 @@ struct taskstats {
__u64 read_bytes; /* bytes of read I/O */
__u64 write_bytes; /* bytes of write I/O */
__u64 cancelled_write_bytes; /* bytes of cancelled write I/O */
__u64 nvcsw; /* voluntary_ctxt_switches */
__u64 nivcsw; /* nonvoluntary_ctxt_switches */
};

View file

@ -196,6 +196,8 @@ static int fill_pid(pid_t pid, struct task_struct *tsk,
/* fill in basic acct fields */
stats->version = TASKSTATS_VERSION;
stats->nvcsw = tsk->nvcsw;
stats->nivcsw = tsk->nivcsw;
bacct_add_tsk(stats, tsk);
/* fill in extended acct fields */
@ -242,6 +244,8 @@ static int fill_tgid(pid_t tgid, struct task_struct *first,
*/
delayacct_add_tsk(stats, tsk);
stats->nvcsw += tsk->nvcsw;
stats->nivcsw += tsk->nivcsw;
} while_each_thread(first, tsk);
unlock_task_sighand(first, &flags);