Don't zero td_runtime when billing thread CPU usage to the process;

maintain a separate td_incruntime to hold unbilled CPU usage for
the thread that has the previous properties of td_runtime.

When thread information is requested using the thread monitoring
sysctls, export thread td_runtime instead of process rusage runtime
in kinfo_proc.

This restores the display of individual ithread and other kernel
thread CPU usage since inception in ps -H and top -SH, as well for
libthr user threads, valuable debugging information lost with the
move to try kthreads since they are no longer independent processes.

There is universal agreement that we should rewrite the process and
thread export sysctls, but this commit gets things going a bit
better in the mean time.  Likewise, there are resevations about the
continued validity of statclock given the speed of modern processors.

Reviewed by:		attilio, emaste, jhb, julian

1 files changed, 4 insertions, 2 deletions

diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c
index 9d02497..ad13c2b 100644
--- a/sys/kern/kern_synch.c
+++ b/sys/kern/kern_synch.c
@@ -371,7 +371,7 @@ wakeup_one(ident)
 void
 mi_switch(int flags, struct thread *newtd)
 {
-	uint64_t new_switchtime;
+	uint64_t runtime, new_switchtime;
 	struct thread *td;
 	struct proc *p;
 
@@ -409,7 +409,9 @@ mi_switch(int flags, struct thread *newtd)
 	 * thread was running, and add that to its total so far.
 	 */
 	new_switchtime = cpu_ticks();
-	td->td_runtime += new_switchtime - PCPU_GET(switchtime);
+	runtime = new_switchtime - PCPU_GET(switchtime);
+	td->td_runtime += runtime;
+	td->td_incruntime += runtime;
 	PCPU_SET(switchtime, new_switchtime);
 	td->td_generation++;	/* bump preempt-detect counter */
 	PCPU_INC(cnt.v_swtch);