[PATCH] Export per-thread resource usage via sysctl

This change exports each individual thread's resource usage via sysctl when 
individual threads are requested via KERN_PROC_INC_THREAD.  This generally 
works correctly with 'top -m io' after the previous change to revert top(1) 
back to using KERN_PROC_PROC when threads are not enabled.  There is one issue 
in that top doesn't necessarily DTRT when disabling/enabling threads via 'H' 
at runtime while in io mode.  I may do some further work to clean that up.  
However, for just top run it will now show per-thread stats instead of 
duplicating the per-process stats for each thread.

It also fixes a bug in that the code in calcru() to try to account for the
current thread's runtime wasn't correctly accounting charging that time to
the current thread.

Index: sys/kern/kern_proc.c
===================================================================
--- sys/kern/kern_proc.c	(revision 224058)
+++ sys/kern/kern_proc.c	(working copy)
_at__at_ -848,6 +848,8 _at__at_
 	kp->ki_tdaddr = td;
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 
+	if (preferthread)
+		PROC_SLOCK(p);
 	thread_lock(td);
 	if (td->td_wmesg != NULL)
 		strlcpy(kp->ki_wmesg, td->td_wmesg, sizeof(kp->ki_wmesg));
_at__at_ -899,6 +901,7 _at__at_
 	kp->ki_pri.pri_user = td->td_user_pri;
 
 	if (preferthread) {
+		rufetchtd(td, &kp->ki_rusage);
 		kp->ki_runtime = cputick2usec(td->td_rux.rux_runtime);
 		kp->ki_pctcpu = sched_pctcpu(td);
 		kp->ki_estcpu = td->td_estcpu;
_at__at_ -911,6 +914,8 _at__at_
 		kp->ki_siglist = td->td_siglist;
 	kp->ki_sigmask = td->td_sigmask;
 	thread_unlock(td);
+	if (preferthread)
+		PROC_SUNLOCK(p);
 }
 
 /*
Index: sys/kern/kern_resource.c
===================================================================
--- sys/kern/kern_resource.c	(revision 224058)
+++ sys/kern/kern_resource.c	(working copy)
_at__at_ -813,7 +813,7 _at__at_
 calcru(struct proc *p, struct timeval *up, struct timeval *sp)
 {
 	struct thread *td;
-	uint64_t u;
+	uint64_t runtime, u;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
 	PROC_SLOCK_ASSERT(p, MA_OWNED);
_at__at_ -826,7 +826,9 _at__at_
 	td = curthread;
 	if (td->td_proc == p) {
 		u = cpu_ticks();
-		p->p_rux.rux_runtime += u - PCPU_GET(switchtime);
+		runtime = u - PCPU_GET(switchtime);
+		td->td_runtime += runtime;
+		td->td_incruntime += runtime;
 		PCPU_SET(switchtime, u);
 	}
 	/* Make sure the per-thread stats are current. */
_at__at_ -838,6 +840,34 _at__at_
 	calcru1(p, &p->p_rux, up, sp);
 }
 
+/* Collect resource usage for a single thread. */
+void
+rufetchtd(struct thread *td, struct rusage *ru)
+{
+	struct proc *p;
+	uint64_t runtime, u;
+
+	p = td->td_proc;
+	PROC_SLOCK_ASSERT(p, MA_OWNED);
+	THREAD_LOCK_ASSERT(td, MA_OWNED);
+	/*
+	 * If we are getting stats for the current thread, then add in the
+	 * stats that this thread has accumulated in its current time slice.
+	 * We reset the thread and CPU state as if we had performed a context
+	 * switch right here.
+	 */
+	if (td == curthread) {
+		u = cpu_ticks();
+		runtime = u - PCPU_GET(switchtime);
+		td->td_runtime += runtime;
+		td->td_incruntime += runtime;
+		PCPU_SET(switchtime, u);
+	}
+	ruxagg(p, td);
+	*ru = td->td_ru;
+	calcru1(p, &td->td_rux, &ru->ru_utime, &ru->ru_stime);
+}
+
 static void
 calcru1(struct proc *p, struct rusage_ext *ruxp, struct timeval *up,
     struct timeval *sp)
_at__at_ -955,12 +985,10 _at__at_
 
 	case RUSAGE_THREAD:
 		PROC_SLOCK(p);
-		ruxagg(p, td);
-		PROC_SUNLOCK(p);
 		thread_lock(td);
-		*rup = td->td_ru;
-		calcru1(p, &td->td_rux, &rup->ru_utime, &rup->ru_stime);
+		rufetchtd(td, rup);
 		thread_unlock(td);
+		PROC_SUNLOCK(p);
 		break;
 
 	default:
Index: sys/sys/resourcevar.h
===================================================================
--- sys/sys/resourcevar.h	(revision 224058)
+++ sys/sys/resourcevar.h	(working copy)
_at__at_ -136,6 +136,7 _at__at_
 void	 rufetch(struct proc *p, struct rusage *ru);
 void	 rufetchcalc(struct proc *p, struct rusage *ru, struct timeval *up,
 	    struct timeval *sp);
+void	 rufetchtd(struct thread *td, struct rusage *ru);
 void	 ruxagg(struct proc *p, struct thread *td);
 int	 suswintr(void *base, int word);
 struct uidinfo

-- 
John Baldwin