diff --git a/lib/libpmc/Makefile b/lib/libpmc/Makefile
index 47f82a6f7cc9..5520bf3b4707 100644
--- a/lib/libpmc/Makefile
+++ b/lib/libpmc/Makefile
@@ -91,6 +91,7 @@ MLINKS+= \
 	pmc_capabilities.3 pmc_pmcinfo.3 \
 	pmc_capabilities.3 pmc_cpuinfo.3 \
 	pmc_capabilities.3 pmc_width.3 \
+	pmc_configure_logfile.3 pmc_close_logfile.3 \
 	pmc_configure_logfile.3 pmc_flush_logfile.3 \
 	pmc_configure_logfile.3 pmc_writelog.3 \
 	pmc_disable.3 pmc_enable.3 \
diff --git a/sys/dev/hwpmc/hwpmc_logging.c b/sys/dev/hwpmc/hwpmc_logging.c
index e76aa9b710eb..f9e1d2f6942a 100644
--- a/sys/dev/hwpmc/hwpmc_logging.c
+++ b/sys/dev/hwpmc/hwpmc_logging.c
@@ -404,7 +404,6 @@ pmclog_loop(void *arg)
 
 	lb = NULL;
 
-
 	/*
 	 * Loop waiting for I/O requests to be added to the owner
 	 * struct's queue.  The loop is exited when the log file
@@ -414,28 +413,25 @@ pmclog_loop(void *arg)
 	mtx_lock(&pmc_kthread_mtx);
 
 	for (;;) {
-
 		/* check if we've been asked to exit */
 		if ((po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)
 			break;
 
-		if (lb == NULL) { /* look for a fresh buffer to write */
-			mtx_lock_spin(&po->po_mtx);
-			if ((lb = TAILQ_FIRST(&po->po_logbuffers)) == NULL) {
-				mtx_unlock_spin(&po->po_mtx);
-
-				/* No more buffers and shutdown required. */
-				if (po->po_flags & PMC_PO_SHUTDOWN)
-					break;
+		/* look for a fresh buffer to write */
+		mtx_lock_spin(&po->po_mtx);
+		if ((lb = TAILQ_FIRST(&po->po_logbuffers)) == NULL) {
+			mtx_unlock_spin(&po->po_mtx);
 
-				(void) msleep(po, &pmc_kthread_mtx, PWAIT,
-				    "pmcloop", 250);
-				continue;
-			}
+			/* No more buffers and shutdown required. */
+			if (po->po_flags & PMC_PO_SHUTDOWN)
+				break;
 
-			TAILQ_REMOVE(&po->po_logbuffers, lb, plb_next);
-			mtx_unlock_spin(&po->po_mtx);
+			(void)msleep(po, &pmc_kthread_mtx, PWAIT, "pmcloop",
+			    250);
+			continue;
 		}
+		TAILQ_REMOVE(&po->po_logbuffers, lb, plb_next);
+		mtx_unlock_spin(&po->po_mtx);
 
 		mtx_unlock(&pmc_kthread_mtx);
 
@@ -487,7 +483,7 @@ pmclog_loop(void *arg)
 
 	wakeup_one(po->po_kthread);
 	po->po_kthread = NULL;
-
+	po->po_flags &= ~PMC_PO_SHUTDOWN;
 	mtx_unlock(&pmc_kthread_mtx);
 
 	/* return the current I/O buffer to the global pool */
@@ -665,7 +661,7 @@ pmclog_stop_kthread(struct pmc_owner *po)
 {
 
 	mtx_lock(&pmc_kthread_mtx);
-	po->po_flags &= ~PMC_PO_OWNS_LOGFILE;
+	po->po_flags &= ~(PMC_PO_OWNS_LOGFILE | PMC_PO_INITIAL_MAPPINGS_DONE);
 	if (po->po_kthread != NULL) {
 		PROC_LOCK(po->po_kthread);
 		kern_psignal(po->po_kthread, SIGHUP);
@@ -693,7 +689,6 @@ pmclog_configure_log(struct pmc_mdep *md, struct pmc_owner *po, int logfd)
 {
 	struct proc *p;
 	struct timespec ts;
-	uint64_t tsc;
 	int error;
 
 	sx_assert(&pmc_sx, SA_XLOCKED);
@@ -722,7 +717,6 @@ pmclog_configure_log(struct pmc_mdep *md, struct pmc_owner *po, int logfd)
 	p->p_flag |= P_HWPMC;
 	PROC_UNLOCK(p);
 	nanotime(&ts);
-	tsc = pmc_rdtsc();
 	/* create a log initialization entry */
 	PMCLOG_RESERVE_WITH_ERROR(po, INITIALIZE,
 	    sizeof(struct pmclog_initialize));
@@ -891,23 +885,24 @@ pmclog_close(struct pmc_owner *po)
 
 	PMCDBG1(LOG,CLO,1, "po=%p", po);
 
-	pmclog_process_closelog(po);
-
 	mtx_lock(&pmc_kthread_mtx);
-	/*
-	 * Initiate shutdown: no new data queued,
-	 * thread will close file on last block.
-	 */
-	po->po_flags |= PMC_PO_SHUTDOWN;
-	/* give time for all to see */
-	DELAY(50);
-	
-	/*
-	 * Schedule the current buffer.
-	 */
-	pmclog_schedule_all(po);
-	wakeup_one(po);
-
+	if (po->po_kthread != NULL) {
+		pmclog_process_closelog(po);
+
+		/*
+		 * Initiate shutdown: no new data queued,
+		 * thread will close file on last block.
+		 */
+		po->po_flags |= PMC_PO_SHUTDOWN;
+		/* give time for all to see */
+		DELAY(50);
+
+		/*
+		 * Schedule the current buffer.
+		 */
+		pmclog_schedule_all(po);
+		wakeup_one(po);
+	}
 	mtx_unlock(&pmc_kthread_mtx);
 
 	return (0);
diff --git a/sys/sys/pmc.h b/sys/sys/pmc.h
index f7831f0ec4b2..5826890b142f 100644
--- a/sys/sys/pmc.h
+++ b/sys/sys/pmc.h
@@ -880,8 +880,11 @@ struct pmc_owner  {
 };
 
 #define	PMC_PO_OWNS_LOGFILE		0x00000001 /* has a log file */
-#define	PMC_PO_SHUTDOWN			0x00000010 /* in the process of shutdown */
-#define	PMC_PO_INITIAL_MAPPINGS_DONE	0x00000020
+#define	PMC_PO_SHUTDOWN			0x00000010 /* shutting down */
+#define	PMC_PO_INITIAL_MAPPINGS_DONE	0x00000020 /*
+						    * kernel mappings have been
+						    * logged
+						    */
 
 /*
  * struct pmc_hw -- describe the state of the PMC hardware