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authorMaxim Uvarov <muvarov@ru.mvista.com>2007-07-15 23:40:48 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-16 09:05:46 -0700
commitb663a79c191508f27cd885224b592a878c0ba0f6 (patch)
tree270a0472bf1fb0c7323ecb60ec68e40d02dcb1b4 /Documentation
parenta6c15c2b0fbfd5c0a84f5f0e1e3f20f85d2b8692 (diff)
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>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/accounting/getdelays.c19
-rw-r--r--Documentation/accounting/taskstats-struct.txt6
2 files changed, 23 insertions, 2 deletions
diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
index 71acc28ed0d..24c5aade899 100644
--- a/Documentation/accounting/getdelays.c
+++ b/Documentation/accounting/getdelays.c
@@ -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");
diff --git a/Documentation/accounting/taskstats-struct.txt b/Documentation/accounting/taskstats-struct.txt
index 661c797eaf7..8aa7529f825 100644
--- a/Documentation/accounting/taskstats-struct.txt
+++ b/Documentation/accounting/taskstats-struct.txt
@@ -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 */
+
}