Author: cem
Date: Fri Mar 25 19:35:29 2016
New Revision: 297273
URL: https://svnweb.freebsd.org/changeset/base/297273
Log:
Add td_swinvoltick to track last involuntary context switch
Expose in DDB via "show thread."
Reviewed by: markj
Sponsored by: EMC / Isilon Storage Division
Modified:
head/sys/ddb/db_ps.c
head/sys/kern/kern_synch.c
head/sys/sys/proc.h
Modified: head/sys/ddb/db_ps.c
==============================================================================
--- head/sys/ddb/db_ps.c Fri Mar 25 19:12:44 2016 (r297272)
+++ head/sys/ddb/db_ps.c Fri Mar 25 19:35:29 2016 (r297273)
@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
#include <sys/cons.h>
#include <sys/jail.h>
#include <sys/kdb.h>
+#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/sysent.h>
#include <sys/systm.h>
@@ -302,6 +303,7 @@ DB_SHOW_COMMAND(thread, db_show_thread)
struct thread *td;
struct lock_object *lock;
bool comma;
+ int delta;
/* Determine which thread to examine. */
if (have_addr)
@@ -376,6 +378,16 @@ DB_SHOW_COMMAND(thread, db_show_thread)
td->td_wchan);
db_printf(" priority: %d\n", td->td_priority);
db_printf(" container lock: %s (%p)\n", lock->lo_name, lock);
+ if (td->td_swvoltick != 0) {
+ delta = (u_int)ticks - (u_int)td->td_swvoltick;
+ db_printf(" last voluntary switch: %d ms ago\n",
+ 1000 * delta / hz);
+ }
+ if (td->td_swinvoltick != 0) {
+ delta = (u_int)ticks - (u_int)td->td_swinvoltick;
+ db_printf(" last involuntary switch: %d ms ago\n",
+ 1000 * delta / hz);
+ }
}
DB_SHOW_COMMAND(proc, db_show_proc)
Modified: head/sys/kern/kern_synch.c
==============================================================================
--- head/sys/kern/kern_synch.c Fri Mar 25 19:12:44 2016 (r297272)
+++ head/sys/kern/kern_synch.c Fri Mar 25 19:35:29 2016 (r297273)
@@ -438,8 +438,10 @@ mi_switch(int flags, struct thread *newt
if (flags & SW_VOL) {
td->td_ru.ru_nvcsw++;
td->td_swvoltick = ticks;
- } else
+ } else {
td->td_ru.ru_nivcsw++;
+ td->td_swinvoltick = ticks;
+ }
#ifdef SCHED_STATS
SCHED_STAT_INC(sched_switch_stats[flags & SW_TYPE_MASK]);
#endif
Modified: head/sys/sys/proc.h
==============================================================================
--- head/sys/sys/proc.h Fri Mar 25 19:12:44 2016 (r297272)
+++ head/sys/sys/proc.h Fri Mar 25 19:35:29 2016 (r297273)
@@ -254,6 +254,7 @@ struct thread {
int td_slptick; /* (t) Time at sleep. */
int td_blktick; /* (t) Time spent blocked. */
int td_swvoltick; /* (t) Time at last SW_VOL switch. */
+ int td_swinvoltick; /* (t) Time at last SW_INVOL switch. */
u_int td_cow; /* (*) Number of copy-on-write faults */
struct rusage td_ru; /* (t) rusage information. */
struct rusage_ext td_rux; /* (t) Internal rusage information. */
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