diff --git a/commands/profile/profile.c b/commands/profile/profile.c
index fe95fb352..a384b5769 100644
--- a/commands/profile/profile.c
+++ b/commands/profile/profile.c
@@ -48,6 +48,7 @@ int action = 0;
 int mem_size = 0;
 int mem_used = 0;
 int freq = 0;
+int intr_type = PROF_RTC;
 char *outfile = "";
 char *mem_ptr;
 int outfile_fd, npipe_fd;
@@ -104,15 +105,27 @@ int main(int argc, char *argv[])
 			break;
 	}
 
+	/*
+	 * Check the frequency when we know the intr type. Only selected values
+	 * are correct for RTC
+	 */
+	if (action == START && intr_type == PROF_RTC && 
+			freq < MIN_FREQ || freq > MAX_FREQ) {
+		printf("Incorrect frequency.\n");
+		return 1;
+	}
+
         printf("Statistical Profiling:\n");
-	printf("  profile start [-m memsize] [-o outfile] [-f frequency]\n");
+	printf("  profile start [--rtc | --nmi] "
+			"[-m memsize] [-o outfile] [-f frequency]\n");
         printf("  profile stop\n\n");
+	printf("   --rtc is default, --nmi allows kernel profiling\n");
         printf("Call Profiling:\n");
 	printf("  profile get   [-m memsize] [-o outfile]\n");
         printf("  profile reset\n\n");
 	printf("   - memsize in MB, default: %u\n", DEF_MEMSIZE);
 	printf("   - default output file: profile.{stat|call}.out\n");
-	printf( "   - sample frequencies (default: %u):\n", DEF_FREQ);
+	printf( "   - sample frequencies for --rtc (default: %u):\n", DEF_FREQ);
 	printf("      3    8192 Hz          10     64 Hz\n");
 	printf("      4    4096 Hz          11     32 Hz\n");
 	printf("      5    2048 Hz          12     16 Hz\n");
@@ -160,13 +173,19 @@ int handle_args(int argc, char *argv[])
 	} else
 	if (strcmp(*argv, "-f") == 0) {
 		if (--argc == 0) return ESYNTAX;
-		if (sscanf(*++argv, "%u", &freq) != 1 ||
-			freq < MIN_FREQ || freq > MAX_FREQ) return EFREQ;
+		if (sscanf(*++argv, "%u", &freq) != 1)
+			return EFREQ;
 	} else
 	if (strcmp(*argv, "-o") == 0) {
 		if (--argc == 0) return ESYNTAX;
 		outfile = *++argv;
 	} else
+	if (strcmp(*argv, "--rtc") == 0) {
+		intr_type = PROF_RTC;
+	} else
+	if (strcmp(*argv, "--nmi") == 0) {
+		intr_type = PROF_NMI;
+	} else
 	if (strcmp(*argv, "start") == 0) {
 		if (action) return EACTION;
 	       	action = START;
@@ -224,7 +243,7 @@ int start()
 
   if (alloc_mem()) return 1;
 
-  if (sprofile(PROF_START, mem_size, freq, &sprof_info, mem_ptr)) {
+  if (sprofile(PROF_START, mem_size, freq, intr_type, &sprof_info, mem_ptr)) {
 	perror("sprofile");
 	printf("Error starting profiling.\n");
 	return 1;
@@ -280,7 +299,7 @@ int stop()
   int n;
   char buf[BUFSIZE];
 
-  if (sprofile(PROF_STOP, 0, 0, 0, 0)) {
+  if (sprofile(PROF_STOP, 0, 0, 0, 0, 0)) {
 	perror("sprofile");
 	printf("Error stopping profiling.\n");
   	return 1;
diff --git a/include/minix/com.h b/include/minix/com.h
index 53e36ce6b..b452f136c 100644
--- a/include/minix/com.h
+++ b/include/minix/com.h
@@ -590,6 +590,7 @@
 #define PROF_MEM_SIZE  m7_i2    /* available memory for data */ 
 #define PROF_FREQ      m7_i3    /* sample frequency */
 #define PROF_ENDPT     m7_i4    /* endpoint of caller */
+#define PROF_INTR_TYPE m7_i5    /* interrupt type */
 #define PROF_CTL_PTR   m7_p1    /* location of info struct */
 #define PROF_MEM_PTR   m7_p2    /* location of profiling data */
 
diff --git a/include/minix/ipc.h b/include/minix/ipc.h
index 5585e4ab0..c74425644 100644
--- a/include/minix/ipc.h
+++ b/include/minix/ipc.h
@@ -22,7 +22,7 @@ typedef struct {long m4l1, m4l2, m4l3, m4l4, m4l5;} mess_4;
 typedef struct {short m5s1, m5s2; int m5i1, m5i2; long m5l1, m5l2, m5l3;}mess_5;
 typedef struct {long m6l1, m6l2, m6l3; short m6s1, m6s2, m6s3; char m6c1, m6c2;
         char *m6p1, *m6p2;} mess_6;
-typedef struct {int m7i1, m7i2, m7i3, m7i4; char *m7p1, *m7p2;} mess_7;
+typedef struct {int m7i1, m7i2, m7i3, m7i4, m7i5; char *m7p1, *m7p2;} mess_7;
 typedef struct {int m8i1, m8i2; char *m8p1, *m8p2, *m8p3, *m8p4;} mess_8;
 typedef struct {long m9l1, m9l2, m9l3, m9l4, m9l5;
 	short m9s1, m9s2, m9s3, m9s4; } mess_9;
@@ -94,6 +94,7 @@ typedef struct {
 #define m7_i2  m_u.m_m7.m7i2
 #define m7_i3  m_u.m_m7.m7i3
 #define m7_i4  m_u.m_m7.m7i4
+#define m7_i5  m_u.m_m7.m7i5
 #define m7_p1  m_u.m_m7.m7p1
 #define m7_p2  m_u.m_m7.m7p2
 
diff --git a/include/minix/profile.h b/include/minix/profile.h
index d78d1ec04..f2e373c95 100644
--- a/include/minix/profile.h
+++ b/include/minix/profile.h
@@ -14,6 +14,9 @@
 #  define PROF_START       0    /* start statistical profiling */
 #  define PROF_STOP        1    /* stop statistical profiling */
 
+#define PROF_RTC	0 /* RTC based profiling */
+#define PROF_NMI	1 /* NMI based profiling, profiles kernel too */
+
 /* Info struct to be copied to from kernel to user program. */
 struct sprof_info_s {
   int mem_used;
@@ -101,7 +104,7 @@ struct cprof_tbl_s {
   u64_t cycles;				/* execution time of path, in cycles */
 } cprof_tbl_inst;
 
-_PROTOTYPE( int sprofile, (int action, int size, int freq, 
+_PROTOTYPE( int sprofile, (int action, int size, int freq, int type,
                                        void *ctl_ptr, void *mem_ptr)   );
 
 _PROTOTYPE( int cprofile, (int action, int size, void *ctl_ptr,
diff --git a/include/minix/syslib.h b/include/minix/syslib.h
index b1a3db189..12850f4c7 100644
--- a/include/minix/syslib.h
+++ b/include/minix/syslib.h
@@ -257,7 +257,7 @@ _PROTOTYPE( int pci_get_bar, (int devind, int port, u32_t *base,
 					u32_t *size, int *ioflag)	);
 
 /* Profiling. */
-_PROTOTYPE( int sys_sprof, (int action, int size, int freq,
+_PROTOTYPE( int sys_sprof, (int action, int size, int freq, int type,
 		endpoint_t endpt, void *ctl_ptr, void *mem_ptr)   );
 _PROTOTYPE( int sys_cprof, (int action, int size, endpoint_t endpt,
                                        void *ctl_ptr, void *mem_ptr)   );
diff --git a/lib/libc/other/_sprofile.c b/lib/libc/other/_sprofile.c
index 2c1bd632e..8d119a547 100644
--- a/lib/libc/other/_sprofile.c
+++ b/lib/libc/other/_sprofile.c
@@ -2,13 +2,19 @@
 
 #define sprofile _sprofile
 
-PUBLIC int sprofile(int action, int size, int freq, char *ctl_ptr, int *mem_ptr)
+PUBLIC int sprofile(int action,
+		int size,
+		int freq,
+		int type,
+		char *ctl_ptr,
+		int *mem_ptr)
 {
   message m;
 
   m.PROF_ACTION         = action;
   m.PROF_MEM_SIZE       = size;
   m.PROF_FREQ           = freq;
+  m.PROF_INTR_TYPE      = type;
   m.PROF_CTL_PTR        = (void *) ctl_ptr;
   m.PROF_MEM_PTR        = (void *) mem_ptr;
 
diff --git a/lib/libsys/sys_sprof.c b/lib/libsys/sys_sprof.c
index 6b72a7221..486cb0da0 100644
--- a/lib/libsys/sys_sprof.c
+++ b/lib/libsys/sys_sprof.c
@@ -5,10 +5,11 @@
 /*===========================================================================*
  *                                sys_sprof				     *
  *===========================================================================*/
-PUBLIC int sys_sprof(action, size, freq, endpt, ctl_ptr, mem_ptr)
+PUBLIC int sys_sprof(action, size, freq, type, endpt, ctl_ptr, mem_ptr)
 int action; 				/* start/stop profiling */
 int size;				/* available profiling memory */
 int freq;				/* sample frequency */
+int type;
 endpoint_t endpt;			/* caller endpoint */
 void *ctl_ptr;				/* location of info struct */
 void *mem_ptr;				/* location of profiling memory */
@@ -18,6 +19,7 @@ void *mem_ptr;				/* location of profiling memory */
   m.PROF_ACTION         = action;
   m.PROF_MEM_SIZE       = size;
   m.PROF_FREQ           = freq;
+  m.PROF_INTR_TYPE      = type;
   m.PROF_ENDPT		= endpt;
   m.PROF_CTL_PTR        = ctl_ptr;
   m.PROF_MEM_PTR        = mem_ptr;
diff --git a/servers/pm/profile.c b/servers/pm/profile.c
index c7a9b07ec..c7e2b06ea 100644
--- a/servers/pm/profile.c
+++ b/servers/pm/profile.c
@@ -38,10 +38,11 @@ PUBLIC int do_sprofile(void)
 		return r;
 
 	return sys_sprof(PROF_START, m_in.PROF_MEM_SIZE, m_in.PROF_FREQ,
+			m_in.PROF_INTR_TYPE,
 			who_e, m_in.PROF_CTL_PTR, m_in.PROF_MEM_PTR);
 
   case PROF_STOP:
-	return sys_sprof(PROF_STOP,0,0,0,0,0);
+	return sys_sprof(PROF_STOP,0,0,0,0,0,0);
 
   default:
 	return EINVAL;