trafgen: fix bug in packet scheduling

When having a config like cpu(1): {...}, and one runs it with -n1, trafgen
behaves buggy, I also noted that in other situations. Fix this by letting
the loop also return on CPU state RES, and do not perform this stupid magic
in the main routine. So far it seems to work now after some basic tests I
did.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

1 files changed, 22 insertions, 16 deletions

diff --git a/trafgen.c b/trafgen.c
index 02aa2df..4bc7a43 100644
--- a/trafgen.c
+++ b/trafgen.c
@@ -498,7 +498,7 @@ static int xmit_smoke_probe(int icmp_sock, struct ctx *ctx)
 	return -1;
 }
 
-static void xmit_slowpath_or_die(struct ctx *ctx, int cpu)
+static void xmit_slowpath_or_die(struct ctx *ctx, int cpu, unsigned long orig_num)
 {
 	int ret, icmp_sock = -1;
 	unsigned long num = 1, i = 0;
@@ -513,6 +513,8 @@ static void xmit_slowpath_or_die(struct ctx *ctx, int cpu)
 
 	if (ctx->num > 0)
 		num = ctx->num;
+	if (ctx->num == 0 && orig_num > 0)
+		num = 0;
 
 	if (ctx->smoke_test)
 		icmp_sock = xmit_smoke_setup(ctx);
@@ -521,7 +523,7 @@ static void xmit_slowpath_or_die(struct ctx *ctx, int cpu)
 
 	bug_on(gettimeofday(&start, NULL));
 
-	while (likely(sigint == 0) && likely(num > 0)) {
+	while (likely(sigint == 0) && likely(num > 0) && likely(plen > 0)) {
 		pktd = &packet_dyn[i];
 		if (pktd->clen + pktd->rlen + pktd->slen) {
 			apply_counter(i);
@@ -584,7 +586,7 @@ retry:
 	stats[cpu].state |= CPU_STATS_STATE_RES;
 }
 
-static void xmit_fastpath_or_die(struct ctx *ctx, int cpu)
+static void xmit_fastpath_or_die(struct ctx *ctx, int cpu, unsigned long orig_num)
 {
 	int ifindex = device_ifindex(ctx->device);
 	uint8_t *out = NULL;
@@ -615,13 +617,15 @@ static void xmit_fastpath_or_die(struct ctx *ctx, int cpu)
 		interval = ctx->kpull;
 	if (ctx->num > 0)
 		num = ctx->num;
+	if (ctx->num == 0 && orig_num > 0)
+		num = 0;
 
 	set_itimer_interval_value(&itimer, 0, interval);
 	setitimer(ITIMER_REAL, &itimer, NULL); 
 
 	bug_on(gettimeofday(&start, NULL));
 
-	while (likely(sigint == 0) && likely(num > 0)) {
+	while (likely(sigint == 0) && likely(num > 0) && likely(plen > 0)) {
 		while (user_may_pull_from_tx(tx_ring.frames[it].iov_base) && likely(num > 0)) {
 			hdr = tx_ring.frames[it].iov_base;
 			out = ((uint8_t *) hdr) + TPACKET2_HDRLEN - sizeof(struct sockaddr_ll);
@@ -694,7 +698,9 @@ static unsigned long __wait_and_sum_others(struct ctx *ctx, int cpu)
 		if (i == cpu)
 			continue;
 
-		while ((__get_state(i) & CPU_STATS_STATE_CFG) == 0 &&
+		while ((__get_state(i) &
+		       (CPU_STATS_STATE_CFG |
+			CPU_STATS_STATE_RES)) == 0 &&
 		       sigint == 0)
 			sched_yield();
 
@@ -714,7 +720,9 @@ static void __correct_global_delta(struct ctx *ctx, int cpu, unsigned long orig)
 		if (i == cpu)
 			continue;
 
-		while ((__get_state(i) & CPU_STATS_STATE_CHK) == 0 &&
+		while ((__get_state(i) &
+		       (CPU_STATS_STATE_CHK |
+			CPU_STATS_STATE_RES)) == 0 &&
 		       sigint == 0)
 			sched_yield();
 
@@ -778,7 +786,7 @@ static int xmit_packet_precheck(struct ctx *ctx, int cpu)
 
 	if (plen == 0) {
 		__set_state(cpu, CPU_STATS_STATE_RES);
-		return -1;
+		return 0;
 	}
 
 	for (mtu = device_mtu(ctx->device), i = 0; i < plen; ++i) {
@@ -792,7 +800,7 @@ static int xmit_packet_precheck(struct ctx *ctx, int cpu)
 }
 
 static void main_loop(struct ctx *ctx, char *confname, bool slow,
-		      int cpu, bool invoke_cpp)
+		      int cpu, bool invoke_cpp, unsigned long orig_num)
 {
 	compile_packets(confname, ctx->verbose, cpu, invoke_cpp);
 	if (xmit_packet_precheck(ctx, cpu) < 0)
@@ -816,9 +824,9 @@ static void main_loop(struct ctx *ctx, char *confname, bool slow,
 	sock = pf_socket();
 
 	if (slow)
-		xmit_slowpath_or_die(ctx, cpu);
+		xmit_slowpath_or_die(ctx, cpu, orig_num);
 	else
-		xmit_fastpath_or_die(ctx, cpu);
+		xmit_fastpath_or_die(ctx, cpu, orig_num);
 
 	close(sock);
 
@@ -845,7 +853,7 @@ int main(int argc, char **argv)
 	bool slow = false, invoke_cpp = false, reseed = true;
 	int c, opt_index, i, j, vals[4] = {0}, irq;
 	char *confname = NULL, *ptr;
-	unsigned long cpus_tmp;
+	unsigned long cpus_tmp, orig_num = 0;
 	unsigned long long tx_packets, tx_bytes;
 	struct ctx ctx;
 
@@ -918,7 +926,8 @@ int main(int argc, char **argv)
 			reseed = false;
 			break;
 		case 'n':
-			ctx.num = strtoul(optarg, NULL, 0);
+			orig_num = strtoul(optarg, NULL, 0);
+			ctx.num = orig_num;
 			break;
 		case 't':
 			slow = true;
@@ -1008,9 +1017,6 @@ int main(int argc, char **argv)
 	irq = device_irq_number(ctx.device);
 	device_set_irq_affinity_list(irq, 0, ctx.cpus - 1);
 
-	if (ctx.num > 0 && ctx.num <= ctx.cpus)
-		ctx.cpus = 1;
-
 	stats = setup_shared_var(ctx.cpus);
 
 	for (i = 0; i < ctx.cpus; i++) {
@@ -1023,7 +1029,7 @@ int main(int argc, char **argv)
 			srand(seed);
 
 			cpu_affinity(i);
-			main_loop(&ctx, confname, slow, i, invoke_cpp);
+			main_loop(&ctx, confname, slow, i, invoke_cpp, orig_num);
 
 			goto thread_out;
 		case -1: