Commit fa24d0b1 authored by Ong Boon Leong's avatar Ong Boon Leong Committed by Alexei Starovoitov
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samples/bpf: xdpsock: Add sched policy and priority support 



By default, TX schedule policy is SCHED_OTHER (round-robin time-sharing).
To improve TX cyclic scheduling, we add SCHED_FIFO policy and its priority
by using -W FIFO or --policy=FIFO and -U <PRIO> or --schpri=<PRIO>.

A) From xdpsock --app-stats, for SCHED_OTHER policy:
   $ xdpsock -i eth0 -t -N -z -T 1000 -b 16 -C 100000 -a

                      period     min        ave        max        cycle
   Cyclic TX          1000000    53507      75334      712642     6250

B) For SCHED_FIFO policy and schpri=50:
   $ xdpsock -i eth0 -t -N -z -T 1000 -b 16 -C 100000 -a -W FIFO -U 50

                      period     min        ave        max        cycle
   Cyclic TX          1000000    3699       24859      54397      6250

Signed-off-by: default avatarOng Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211230035447.523177-6-boon.leong.ong@intel.com
parent fa0d27a1

samples/bpf/xdpsock_user.c

+59 −2
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <sys/un.h>

#include <time.h>

#include <unistd.h>

#include <sched.h>



#include <bpf/libbpf.h>

#include <bpf/xsk.h>
@@ -66,6 +67,8 @@ 
#define NSEC_PER_SEC		1000000000UL

#define NSEC_PER_USEC		1000



#define SCHED_PRI__DEFAULT	0



typedef __u64 u64;

typedef __u32 u32;

typedef __u16 u16;
@@ -123,6 +126,8 @@ static bool opt_busy_poll; 
static bool opt_reduced_cap;

static clockid_t opt_clock = CLOCK_MONOTONIC;

static unsigned long opt_tx_cycle_ns;

static int opt_schpolicy = SCHED_OTHER;

static int opt_schprio = SCHED_PRI__DEFAULT;



struct vlan_ethhdr {

	unsigned char h_dest[6];
@@ -198,6 +203,15 @@ static const struct clockid_map { 
	{ NULL }

};



static const struct sched_map {

	const char *name;

	int policy;

} schmap[] = {

	{ "OTHER", SCHED_OTHER },

	{ "FIFO", SCHED_FIFO },

	{ NULL }

};



static int num_socks;

struct xsk_socket_info *xsks[MAX_SOCKS];

int sock;
@@ -216,6 +230,20 @@ static int get_clockid(clockid_t *id, const char *name) 
	return -1;

}



static int get_schpolicy(int *policy, const char *name)

{

	const struct sched_map *sch;



	for (sch = schmap; sch->name; sch++) {

		if (strcasecmp(sch->name, name) == 0) {

			*policy = sch->policy;

			return 0;

		}

	}



	return -1;

}



static unsigned long get_nsecs(void)

{

	struct timespec ts;
@@ -1019,6 +1047,8 @@ static struct option long_options[] = { 
	{"tx-dmac", required_argument, 0, 'G'},

	{"tx-smac", required_argument, 0, 'H'},

	{"tx-cycle", required_argument, 0, 'T'},

	{"policy", required_argument, 0, 'W'},

	{"schpri", required_argument, 0, 'U'},

	{"extra-stats", no_argument, 0, 'x'},

	{"quiet", no_argument, 0, 'Q'},

	{"app-stats", no_argument, 0, 'a'},
@@ -1066,6 +1096,8 @@ static void usage(const char *prog) 
		"  -G, --tx-dmac=<MAC>  Dest MAC addr of TX frame in aa:bb:cc:dd:ee:ff format (For -V|--tx-vlan)\n"

		"  -H, --tx-smac=<MAC>  Src MAC addr of TX frame in aa:bb:cc:dd:ee:ff format (For -V|--tx-vlan)\n"

		"  -T, --tx-cycle=n     Tx cycle time in micro-seconds (For -t|--txonly).\n"

		"  -W, --policy=POLICY  Schedule policy. Default: SCHED_OTHER\n"

		"  -U, --schpri=n       Schedule priority. Default: %d\n"

		"  -x, --extra-stats	Display extra statistics.\n"

		"  -Q, --quiet          Do not display any stats.\n"

		"  -a, --app-stats	Display application (syscall) statistics.\n"
@@ -1076,7 +1108,8 @@ static void usage(const char *prog) 
	fprintf(stderr, str, prog, XSK_UMEM__DEFAULT_FRAME_SIZE,

		opt_batch_size, MIN_PKT_SIZE, MIN_PKT_SIZE,

		XSK_UMEM__DEFAULT_FRAME_SIZE, opt_pkt_fill_pattern,

		VLAN_VID__DEFAULT, VLAN_PRI__DEFAULT);

		VLAN_VID__DEFAULT, VLAN_PRI__DEFAULT,

		SCHED_PRI__DEFAULT);



	exit(EXIT_FAILURE);

}
@@ -1088,7 +1121,8 @@ static void parse_command_line(int argc, char **argv) 
	opterr = 0;



	for (;;) {

		c = getopt_long(argc, argv, "Frtli:q:pSNn:w:czf:muMd:b:C:s:P:VJ:K:G:H:T:xQaI:BR",

		c = getopt_long(argc, argv,

				"Frtli:q:pSNn:w:czf:muMd:b:C:s:P:VJ:K:G:H:T:W:U:xQaI:BR",

				long_options, &option_index);

		if (c == -1)

			break;
@@ -1206,6 +1240,17 @@ static void parse_command_line(int argc, char **argv) 
			opt_tx_cycle_ns = atoi(optarg);

			opt_tx_cycle_ns *= NSEC_PER_USEC;

			break;

		case 'W':

			if (get_schpolicy(&opt_schpolicy, optarg)) {

				fprintf(stderr,

					"ERROR: Invalid policy %s. Default to SCHED_OTHER.\n",

					optarg);

				opt_schpolicy = SCHED_OTHER;

			}

			break;

		case 'U':

			opt_schprio = atoi(optarg);

			break;

		case 'x':

			opt_extra_stats = 1;

			break;
@@ -1780,6 +1825,7 @@ int main(int argc, char **argv) 
	struct __user_cap_data_struct data[2] = { { 0 } };

	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};

	bool rx = false, tx = false;

	struct sched_param schparam;

	struct xsk_umem_info *umem;

	struct bpf_object *obj;

	int xsks_map_fd = 0;
@@ -1881,6 +1927,16 @@ int main(int argc, char **argv) 
	prev_time = get_nsecs();

	start_time = prev_time;



	/* Configure sched priority for better wake-up accuracy */

	memset(&schparam, 0, sizeof(schparam));

	schparam.sched_priority = opt_schprio;

	ret = sched_setscheduler(0, opt_schpolicy, &schparam);

	if (ret) {

		fprintf(stderr, "Error(%d) in setting priority(%d): %s\n",

			errno, opt_schprio, strerror(errno));

		goto out;

	}



	if (opt_bench == BENCH_RXDROP)

		rx_drop_all();

	else if (opt_bench == BENCH_TXONLY)
@@ -1888,6 +1944,7 @@ int main(int argc, char **argv) 
	else

		l2fwd_all();



out:

	benchmark_done = true;



	if (!opt_quiet)