Index: head/sys/compat/linux/linux_misc.h
===================================================================
--- head/sys/compat/linux/linux_misc.h
+++ head/sys/compat/linux/linux_misc.h
@@ -105,6 +105,8 @@
 #define	LINUX_SCHED_FIFO	1
 #define	LINUX_SCHED_RR		2
 
+#define	LINUX_MAX_RT_PRIO	100
+
 struct l_new_utsname {
 	char	sysname[LINUX_MAX_UTSNAME];
 	char	nodename[LINUX_MAX_UTSNAME];
Index: head/sys/compat/linux/linux_misc.c
===================================================================
--- head/sys/compat/linux/linux_misc.c
+++ head/sys/compat/linux/linux_misc.c
@@ -144,6 +144,11 @@
 	l_size_t	ss_len;
 };
 
+static bool map_sched_prio = true;
+SYSCTL_BOOL(_compat_linux, OID_AUTO, map_sched_prio, CTLFLAG_RDTUN,
+    &map_sched_prio, 0, "Map scheduler priorities to Linux priorities "
+    "(not POSIX compliant)");
+
 static int	linux_utimensat_nsec_valid(l_long);
 
 
@@ -1419,6 +1424,33 @@
 	if (error)
 		return (error);
 
+	if (map_sched_prio) {
+		switch (policy) {
+		case SCHED_OTHER:
+			if (sched_param.sched_priority != 0)
+				return (EINVAL);
+
+			sched_param.sched_priority =
+			    PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE;
+			break;
+		case SCHED_FIFO:
+		case SCHED_RR:
+			if (sched_param.sched_priority < 1 ||
+			    sched_param.sched_priority >= LINUX_MAX_RT_PRIO)
+				return (EINVAL);
+
+			/*
+			 * Map [1, LINUX_MAX_RT_PRIO - 1] to
+			 * [0, RTP_PRIO_MAX - RTP_PRIO_MIN] (rounding down).
+			 */
+			sched_param.sched_priority =
+			    (sched_param.sched_priority - 1) *
+			    (RTP_PRIO_MAX - RTP_PRIO_MIN + 1) /
+			    (LINUX_MAX_RT_PRIO - 1);
+			break;
+		}
+	}
+
 	tdt = linux_tdfind(td, args->pid, -1);
 	if (tdt == NULL)
 		return (ESRCH);
@@ -1462,6 +1494,20 @@
 {
 	struct sched_get_priority_max_args bsd;
 
+	if (map_sched_prio) {
+		switch (args->policy) {
+		case LINUX_SCHED_OTHER:
+			td->td_retval[0] = 0;
+			return (0);
+		case LINUX_SCHED_FIFO:
+		case LINUX_SCHED_RR:
+			td->td_retval[0] = LINUX_MAX_RT_PRIO - 1;
+			return (0);
+		default:
+			return (EINVAL);
+		}
+	}
+
 	switch (args->policy) {
 	case LINUX_SCHED_OTHER:
 		bsd.policy = SCHED_OTHER;
@@ -1484,6 +1530,20 @@
 {
 	struct sched_get_priority_min_args bsd;
 
+	if (map_sched_prio) {
+		switch (args->policy) {
+		case LINUX_SCHED_OTHER:
+			td->td_retval[0] = 0;
+			return (0);
+		case LINUX_SCHED_FIFO:
+		case LINUX_SCHED_RR:
+			td->td_retval[0] = 1;
+			return (0);
+		default:
+			return (EINVAL);
+		}
+	}
+
 	switch (args->policy) {
 	case LINUX_SCHED_OTHER:
 		bsd.policy = SCHED_OTHER;
@@ -1864,7 +1924,7 @@
 {
 	struct sched_param sched_param;
 	struct thread *tdt;
-	int error;
+	int error, policy;
 
 	error = copyin(uap->param, &sched_param, sizeof(sched_param));
 	if (error)
@@ -1874,8 +1934,41 @@
 	if (tdt == NULL)
 		return (ESRCH);
 
+	if( map_sched_prio ) {
+		error = kern_sched_getscheduler(td, tdt, &policy);
+		if (error)
+			goto out;
+
+		switch (policy) {
+		case SCHED_OTHER:
+			if (sched_param.sched_priority != 0) {
+				error = EINVAL;
+				goto out;
+			}
+			sched_param.sched_priority =
+			    PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE;
+			break;
+		case SCHED_FIFO:
+		case SCHED_RR:
+			if (sched_param.sched_priority < 1 ||
+			    sched_param.sched_priority >= LINUX_MAX_RT_PRIO) {
+				error = EINVAL;
+				goto out;
+			}
+			/*
+			 * Map [1, LINUX_MAX_RT_PRIO - 1] to
+			 * [0, RTP_PRIO_MAX - RTP_PRIO_MIN] (rounding down).
+			 */
+			sched_param.sched_priority =
+			    (sched_param.sched_priority - 1) *
+			    (RTP_PRIO_MAX - RTP_PRIO_MIN + 1) /
+			    (LINUX_MAX_RT_PRIO - 1);
+			break;
+		}
+	}
+
 	error = kern_sched_setparam(td, tdt, &sched_param);
-	PROC_UNLOCK(tdt->td_proc);
+out:	PROC_UNLOCK(tdt->td_proc);
 	return (error);
 }
 
@@ -1885,17 +1978,45 @@
 {
 	struct sched_param sched_param;
 	struct thread *tdt;
-	int error;
+	int error, policy;
 
 	tdt = linux_tdfind(td, uap->pid, -1);
 	if (tdt == NULL)
 		return (ESRCH);
 
 	error = kern_sched_getparam(td, tdt, &sched_param);
-	PROC_UNLOCK(tdt->td_proc);
-	if (error == 0)
-		error = copyout(&sched_param, uap->param,
-		    sizeof(sched_param));
+	if (error) {
+		PROC_UNLOCK(tdt->td_proc);
+		return (error);
+	}
+
+	if (map_sched_prio) {
+		error = kern_sched_getscheduler(td, tdt, &policy);
+		PROC_UNLOCK(tdt->td_proc);
+		if (error)
+			return (error);
+
+		switch (policy) {
+		case SCHED_OTHER:
+			sched_param.sched_priority = 0;
+			break;
+		case SCHED_FIFO:
+		case SCHED_RR:
+			/*
+			 * Map [0, RTP_PRIO_MAX - RTP_PRIO_MIN] to
+			 * [1, LINUX_MAX_RT_PRIO - 1] (rounding up).
+			 */
+			sched_param.sched_priority =
+			    (sched_param.sched_priority *
+			    (LINUX_MAX_RT_PRIO - 1) +
+			    (RTP_PRIO_MAX - RTP_PRIO_MIN - 1)) /
+			    (RTP_PRIO_MAX - RTP_PRIO_MIN) + 1;
+			break;
+		}
+	} else
+		PROC_UNLOCK(tdt->td_proc);
+
+	error = copyout(&sched_param, uap->param, sizeof(sched_param));
 	return (error);
 }