pktgen: increasing transmission granularity

This patch increases the granularity of the rate generated by pktgen.
The previous version of pktgen uses micro seconds (udelay) resolution when it
was delayed causing gaps in the rates. It is changed to nanosecond (ndelay).
Now any rate is possible.

Also it allows to set, the desired rate in Mb/s or packets per second.

The documentation has been updated.

Signed-off-by: Daniel Turull <[e-mail]>
Signed-off-by: Robert Olsson <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

Documentation/networking/pktgen.txt

···
 
  pgset stop    	          aborts injection. Also, ^C aborts generator.
 
+ pgset "rate 300M"        set rate to 300 Mb/s
+ pgset "ratep 1000000"    set rate to 1Mpps
 
 Example scripts
 ===============
···
 
 flows
 flowlen
+
+rate
+ratep
 
 References:
 ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/

net/core/pktgen.c

···
 #include <asm/dma.h>
 #include <asm/div64.h>		/* do_div */
 
-#define VERSION 	"2.73"
+#define VERSION	"2.74"
 #define IP_NAME_SZ 32
 #define MAX_MPLS_LABELS 16 /* This is the max label stack depth */
 #define MPLS_STACK_BOTTOM htonl(0x00000100)
···
 
 		sprintf(pg_result, "OK: delay=%llu",
 			(unsigned long long) pkt_dev->delay);
+		return count;
+	}
+	if (!strcmp(name, "rate")) {
+		len = num_arg(&user_buffer[i], 10, &value);
+		if (len < 0)
+			return len;
+
+		i += len;
+		if (!value)
+			return len;
+		pkt_dev->delay = pkt_dev->min_pkt_size*8*NSEC_PER_USEC/value;
+		if (debug)
+			printk(KERN_INFO
+				 "pktgen: Delay set at: %llu ns\n",
+					pkt_dev->delay);
+
+		sprintf(pg_result, "OK: rate=%lu", value);
+		return count;
+	}
+	if (!strcmp(name, "ratep")) {
+		len = num_arg(&user_buffer[i], 10, &value);
+		if (len < 0)
+			return len;
+
+		i += len;
+		if (!value)
+			return len;
+		pkt_dev->delay = NSEC_PER_SEC/value;
+		if (debug)
+			printk(KERN_INFO
+				 "pktgen: Delay set at: %llu ns\n",
+					pkt_dev->delay);
+
+		sprintf(pg_result, "OK: rate=%lu", value);
 		return count;
 	}
 	if (!strcmp(name, "udp_src_min")) {
···
 	hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 	hrtimer_set_expires(&t.timer, spin_until);
 
-	remaining = ktime_to_us(hrtimer_expires_remaining(&t.timer));
+	remaining = ktime_to_ns(hrtimer_expires_remaining(&t.timer));
 	if (remaining <= 0) {
 		pkt_dev->next_tx = ktime_add_ns(spin_until, pkt_dev->delay);
 		return;
 	}
 
 	start_time = ktime_now();
-	if (remaining < 100)
-		udelay(remaining); 	/* really small just spin */
+	if (remaining < 100000)
+		ndelay(remaining);	/* really small just spin */
 	else {
 		/* see do_nanosleep */
 		hrtimer_init_sleeper(&t, current);