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samples/bpf: xdpsock: Add cyclic TX operation capability
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Tx cycle time is in micro-seconds unit. By combining the batch size (-b M)
and Tx cycle time (-T|--tx-cycle N), xdpsock now can transmit batch-size of
packets every N-us periodically. Cyclic TX operation is not applicable if
--poll mode is used.

To transmit 16 packets every 1ms cycle time for total of 100000 packets
silently:
 $ xdpsock -i eth0 -T -N -z -T 1000 -b 16 -C 100000

To print cyclic TX schedule variance stats, use --app-stats|-a:
 $ xdpsock -i eth0 -T -N -z -T 1000 -b 16 -C 100000 -a

 sock0@eth0:0 txonly xdp-drv
                   pps            pkts           0.00
rx                 0              0
tx                 0              100000

                   calls/s        count
rx empty polls     0              0
fill fail polls    0              0
copy tx sendtos    0              0
tx wakeup sendtos  0              6254
opt polls          0              0

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

Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211230035447.523177-5-boon.leong.ong@intel.com
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Ong Boon Leong authored and Alexei Starovoitov committed Jan 6, 2022
1 parent 5a38825 commit fa0d27a
Showing 1 changed file with 80 additions and 5 deletions.
85 changes: 80 additions & 5 deletions samples/bpf/xdpsock_user.c
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Original file line number Diff line number Diff line change
Expand Up @@ -63,12 +63,19 @@
#define VLAN_VID__DEFAULT 1
#define VLAN_PRI__DEFAULT 0

#define NSEC_PER_SEC 1000000000UL
#define NSEC_PER_USEC 1000

typedef __u64 u64;
typedef __u32 u32;
typedef __u16 u16;
typedef __u8 u8;

static unsigned long prev_time;
static long tx_cycle_diff_min;
static long tx_cycle_diff_max;
static double tx_cycle_diff_ave;
static long tx_cycle_cnt;

enum benchmark_type {
BENCH_RXDROP = 0,
Expand Down Expand Up @@ -115,6 +122,7 @@ static u32 prog_id;
static bool opt_busy_poll;
static bool opt_reduced_cap;
static clockid_t opt_clock = CLOCK_MONOTONIC;
static unsigned long opt_tx_cycle_ns;

struct vlan_ethhdr {
unsigned char h_dest[6];
Expand Down Expand Up @@ -305,6 +313,15 @@ static void dump_app_stats(long dt)
xsks[i]->app_stats.prev_tx_wakeup_sendtos = xsks[i]->app_stats.tx_wakeup_sendtos;
xsks[i]->app_stats.prev_opt_polls = xsks[i]->app_stats.opt_polls;
}

if (opt_tx_cycle_ns) {
printf("\n%-18s %-10s %-10s %-10s %-10s %-10s\n",
"", "period", "min", "ave", "max", "cycle");
printf("%-18s %-10lu %-10lu %-10lu %-10lu %-10lu\n",
"Cyclic TX", opt_tx_cycle_ns, tx_cycle_diff_min,
(long)(tx_cycle_diff_ave / tx_cycle_cnt),
tx_cycle_diff_max, tx_cycle_cnt);
}
}

static bool get_interrupt_number(void)
Expand Down Expand Up @@ -1001,6 +1018,7 @@ static struct option long_options[] = {
{"tx-vlan-pri", required_argument, 0, 'K'},
{"tx-dmac", required_argument, 0, 'G'},
{"tx-smac", required_argument, 0, 'H'},
{"tx-cycle", required_argument, 0, 'T'},
{"extra-stats", no_argument, 0, 'x'},
{"quiet", no_argument, 0, 'Q'},
{"app-stats", no_argument, 0, 'a'},
Expand Down Expand Up @@ -1047,6 +1065,7 @@ static void usage(const char *prog)
" -K, --tx-vlan-pri=n Tx VLAN Priority [0-7]. Default: %d (For -V|--tx-vlan)\n"
" -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"
" -x, --extra-stats Display extra statistics.\n"
" -Q, --quiet Do not display any stats.\n"
" -a, --app-stats Display application (syscall) statistics.\n"
Expand All @@ -1069,7 +1088,7 @@ 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:xQaI:BR",
c = getopt_long(argc, argv, "Frtli:q:pSNn:w:czf:muMd:b:C:s:P:VJ:K:G:H:T:xQaI:BR",
long_options, &option_index);
if (c == -1)
break;
Expand Down Expand Up @@ -1183,6 +1202,10 @@ static void parse_command_line(int argc, char **argv)
usage(basename(argv[0]));
}
break;
case 'T':
opt_tx_cycle_ns = atoi(optarg);
opt_tx_cycle_ns *= NSEC_PER_USEC;
break;
case 'x':
opt_extra_stats = 1;
break;
Expand Down Expand Up @@ -1388,7 +1411,7 @@ static void rx_drop_all(void)
}
}

static void tx_only(struct xsk_socket_info *xsk, u32 *frame_nb, int batch_size)
static int tx_only(struct xsk_socket_info *xsk, u32 *frame_nb, int batch_size)
{
u32 idx;
unsigned int i;
Expand All @@ -1397,7 +1420,7 @@ static void tx_only(struct xsk_socket_info *xsk, u32 *frame_nb, int batch_size)
batch_size) {
complete_tx_only(xsk, batch_size);
if (benchmark_done)
return;
return 0;
}

for (i = 0; i < batch_size; i++) {
Expand All @@ -1413,6 +1436,8 @@ static void tx_only(struct xsk_socket_info *xsk, u32 *frame_nb, int batch_size)
*frame_nb += batch_size;
*frame_nb %= NUM_FRAMES;
complete_tx_only(xsk, batch_size);

return batch_size;
}

static inline int get_batch_size(int pkt_cnt)
Expand Down Expand Up @@ -1446,16 +1471,39 @@ static void tx_only_all(void)
{
struct pollfd fds[MAX_SOCKS] = {};
u32 frame_nb[MAX_SOCKS] = {};
unsigned long next_tx_ns = 0;
int pkt_cnt = 0;
int i, ret;

if (opt_poll && opt_tx_cycle_ns) {
fprintf(stderr,
"Error: --poll and --tx-cycles are both set\n");
return;
}

for (i = 0; i < num_socks; i++) {
fds[0].fd = xsk_socket__fd(xsks[i]->xsk);
fds[0].events = POLLOUT;
}

if (opt_tx_cycle_ns) {
/* Align Tx time to micro-second boundary */
next_tx_ns = (get_nsecs() / NSEC_PER_USEC + 1) *
NSEC_PER_USEC;
next_tx_ns += opt_tx_cycle_ns;

/* Initialize periodic Tx scheduling variance */
tx_cycle_diff_min = 1000000000;
tx_cycle_diff_max = 0;
tx_cycle_diff_ave = 0.0;
}

while ((opt_pkt_count && pkt_cnt < opt_pkt_count) || !opt_pkt_count) {
int batch_size = get_batch_size(pkt_cnt);
struct timespec next;
int tx_cnt = 0;
long diff;
int err;

if (opt_poll) {
for (i = 0; i < num_socks; i++)
Expand All @@ -1468,13 +1516,40 @@ static void tx_only_all(void)
continue;
}

if (opt_tx_cycle_ns) {
next.tv_sec = next_tx_ns / NSEC_PER_SEC;
next.tv_nsec = next_tx_ns % NSEC_PER_SEC;
err = clock_nanosleep(opt_clock, TIMER_ABSTIME, &next, NULL);
if (err) {
if (err != EINTR)
fprintf(stderr,
"clock_nanosleep failed. Err:%d errno:%d\n",
err, errno);
break;
}

/* Measure periodic Tx scheduling variance */
diff = get_nsecs() - next_tx_ns;
if (diff < tx_cycle_diff_min)
tx_cycle_diff_min = diff;

if (diff > tx_cycle_diff_max)
tx_cycle_diff_max = diff;

tx_cycle_diff_ave += (double)diff;
tx_cycle_cnt++;
}

for (i = 0; i < num_socks; i++)
tx_only(xsks[i], &frame_nb[i], batch_size);
tx_cnt += tx_only(xsks[i], &frame_nb[i], batch_size);

pkt_cnt += batch_size;
pkt_cnt += tx_cnt;

if (benchmark_done)
break;

if (opt_tx_cycle_ns)
next_tx_ns += opt_tx_cycle_ns;
}

if (opt_pkt_count)
Expand Down

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