diff mbox series

[RFC,v2,3/4] liburing: add test programs for napi busy poll

Message ID 20221107175357.2733763-4-shr@devkernel.io (mailing list archive)
State New
Headers show
Series liburing: add api for napi busy poll timeout | expand

Commit Message

Stefan Roesch Nov. 7, 2022, 5:53 p.m. UTC
This adds two test programs to test the napi busy poll functionality. It
consists of a client program and a server program. To get a napi id, the
client and the server program need to be run on different hosts.

To test the napi busy poll timeout, the -t needs to be specified. A
reasonable value for the busy poll timeout is 100. By specifying the
busy poll timeout on the server and the client the best results are
accomplished.

Signed-off-by: Stefan Roesch <shr@devkernel.io>
---
 test/Makefile                |   2 +
 test/napi-busy-poll-client.c | 422 +++++++++++++++++++++++++++++++++++
 test/napi-busy-poll-server.c | 372 ++++++++++++++++++++++++++++++
 3 files changed, 796 insertions(+)
 create mode 100644 test/napi-busy-poll-client.c
 create mode 100644 test/napi-busy-poll-server.c

Comments

Ammar Faizi Nov. 8, 2022, 7:01 a.m. UTC | #1
On 11/8/22 12:53 AM, Stefan Roesch wrote:
> This adds two test programs to test the napi busy poll functionality. It
> consists of a client program and a server program. To get a napi id, the
> client and the server program need to be run on different hosts.
> 
> To test the napi busy poll timeout, the -t needs to be specified. A
> reasonable value for the busy poll timeout is 100. By specifying the
> busy poll timeout on the server and the client the best results are
> accomplished.
> 
> Signed-off-by: Stefan Roesch <shr@devkernel.io>
> ---
>   test/Makefile                |   2 +
>   test/napi-busy-poll-client.c | 422 +++++++++++++++++++++++++++++++++++
>   test/napi-busy-poll-server.c | 372 ++++++++++++++++++++++++++++++
>   3 files changed, 796 insertions(+)
>   create mode 100644 test/napi-busy-poll-client.c
>   create mode 100644 test/napi-busy-poll-server.c

Hi Stefan,

We don't write liburing tests this way. Your new tests break the "make runtests"
command:

   ...
   ...
   Running test napi-busy-poll-client.t                                address option is mandatory
   Usage: ./napi-busy-poll-client.t [-l|--listen] [-a|--address ip_address] [-p|--port port-no] [-s|--sqpoll] [-b|--busy] [-n|--num pings] [-t|--timeout busy-poll-timeout] [-h|--help]
   ... snip ...

   Test napi-busy-poll-client.t failed with ret 1
   Running test napi-busy-poll-server.t                                address option is mandatory
   Usage: ./napi-busy-poll-server.t [-l|--listen] [-a|--address ip_address] [-p|--port port-no] [-s|--sqpoll] [-b|--busy] [-n|--num pings] [-t|--timeout busy-poll-timeout] [-h|--help]
   ... snip ...
   ...
   ...
   Tests failed (3): <napi-busy-poll-client.t> <napi-busy-poll-server.t> <pipe-bug.t>
   make[1]: *** [Makefile:235: runtests] Error 1
   make[1]: Leaving directory '/home/ammarfaizi2/app/liburing/test'
   make: *** [Makefile:21: runtests] Error 2

All test programs in the "test/" directory are run by "make runtests" command.
Please try to run them with "make runtests" command.

If you want to test several arguments combination variants, you can do something
like this:

    https://github.com/axboe/liburing/blob/754bc068ec482/test/socket.c#L369-L409

Note: Since you're adding a new feature, your test program should check whether
the running kernel supports the new feature. If the running kernel doesn't
support it, use T_EXIT_SKIP as the exit code.
Ammar Faizi Nov. 8, 2022, 9:47 a.m. UTC | #2
On 11/8/22 2:01 PM, Ammar Faizi wrote:
> On 11/8/22 12:53 AM, Stefan Roesch wrote:
>> This adds two test programs to test the napi busy poll functionality. It
>> consists of a client program and a server program. To get a napi id, the
>> client and the server program need to be run on different hosts.
>>
>> To test the napi busy poll timeout, the -t needs to be specified. A
>> reasonable value for the busy poll timeout is 100. By specifying the
>> busy poll timeout on the server and the client the best results are
>> accomplished.
>>
>> Signed-off-by: Stefan Roesch <shr@devkernel.io>
>> ---
>>   test/Makefile                |   2 +
>>   test/napi-busy-poll-client.c | 422 +++++++++++++++++++++++++++++++++++
>>   test/napi-busy-poll-server.c | 372 ++++++++++++++++++++++++++++++
>>   3 files changed, 796 insertions(+)
>>   create mode 100644 test/napi-busy-poll-client.c
>>   create mode 100644 test/napi-busy-poll-server.c
> 
> Hi Stefan,
> 
> We don't write liburing tests this way. Your new tests break the "make runtests"
> command:
> 
>    ...
>    ...
>    Running test napi-busy-poll-client.t                                address option is mandatory
>    Usage: ./napi-busy-poll-client.t [-l|--listen] [-a|--address ip_address] [-p|--port port-no] [-s|--sqpoll] [-b|--busy] [-n|--num pings] [-t|--timeout busy-poll-timeout] [-h|--help]
>    ... snip ...
> 
>    Test napi-busy-poll-client.t failed with ret 1
>    Running test napi-busy-poll-server.t                                address option is mandatory
>    Usage: ./napi-busy-poll-server.t [-l|--listen] [-a|--address ip_address] [-p|--port port-no] [-s|--sqpoll] [-b|--busy] [-n|--num pings] [-t|--timeout busy-poll-timeout] [-h|--help]
>    ... snip ...
>    ...
>    ...
>    Tests failed (3): <napi-busy-poll-client.t> <napi-busy-poll-server.t> <pipe-bug.t>
>    make[1]: *** [Makefile:235: runtests] Error 1
>    make[1]: Leaving directory '/home/ammarfaizi2/app/liburing/test'
>    make: *** [Makefile:21: runtests] Error 2
> 
> All test programs in the "test/" directory are run by "make runtests" command.
> Please try to run them with "make runtests" command.
> 
> If you want to test several arguments combination variants, you can do something
> like this:
> 
>     https://github.com/axboe/liburing/blob/754bc068ec482/test/socket.c#L369-L409
> 
> Note: Since you're adding a new feature, your test program should check whether
> the running kernel supports the new feature. If the running kernel doesn't
> support it, use T_EXIT_SKIP as the exit code.

Note: In that example, it doesn't use T_EXIT_* as the exit code because this
exit code protocol is a new framework. We haven't finished to port the old
tests to follow this rule.

It's introduced in commit (in liburing-2.3):

    ed430fbeb3336 ("tests: migrate some tests to use enum-based exit codes")

New tests should follow the T_EXIT_* convention for exit code.
diff mbox series

Patch

diff --git a/test/Makefile b/test/Makefile
index 8263e9f..8c606f9 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -105,6 +105,8 @@  test_srcs := \
 	mkdir.c \
 	msg-ring.c \
 	multicqes_drain.c \
+	napi-busy-poll-client.c \
+	napi-busy-poll-server.c \
 	nolibc.c \
 	nop-all-sizes.c \
 	nop.c \
diff --git a/test/napi-busy-poll-client.c b/test/napi-busy-poll-client.c
new file mode 100644
index 0000000..0ae4afa
--- /dev/null
+++ b/test/napi-busy-poll-client.c
@@ -0,0 +1,422 @@ 
+#include <ctype.h>
+#include <errno.h>
+#include <float.h>
+#include <getopt.h>
+#include <liburing.h>
+#include <math.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <time.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <netinet/in.h>
+
+#include "helpers.h"
+
+#define MAXBUFLEN 100
+#define PORTNOLEN 10
+#define ADDRLEN   80
+#define RINGSIZE  1024
+
+#define printable(ch) (isprint((unsigned char)ch) ? ch : '#')
+
+enum {
+	IOURING_RECV,
+	IOURING_SEND,
+	IOURING_RECVMSG,
+	IOURING_SENDMSG
+};
+
+struct ctx
+{
+	struct io_uring ring;
+	struct sockaddr_in6 saddr;
+
+	int sockfd;
+	int buffer_len;
+	int num_pings;
+	bool napi_check;
+
+	union {
+		char buffer[MAXBUFLEN];
+		struct timespec ts;
+	};
+
+	int rtt_index;
+	double *rtt;
+} ctx;
+
+struct options
+{
+	int  num_pings;
+	int  timeout;
+	bool sq_poll;
+	bool busy_loop;
+	char port[PORTNOLEN];
+	char addr[ADDRLEN];
+} options;
+
+struct option longopts[] =
+{
+	{"address"  , 1, NULL, 'a'},
+	{"busy"     , 0, NULL, 'b'},
+	{"help"     , 0, NULL, 'h'},
+	{"num_pings", 1, NULL, 'n'},
+	{"port"     , 1, NULL, 'p'},
+	{"sqpoll"   , 0, NULL, 's'},
+	{"timeout"  , 1, NULL, 't'},
+	{NULL       , 0, NULL,  0 }
+};
+
+void printUsage(const char *name)
+{
+	fprintf(stderr,
+	"Usage: %s [-l|--listen] [-a|--address ip_address] [-p|--port port-no] [-s|--sqpoll]"
+	" [-b|--busy] [-n|--num pings] [-t|--timeout busy-poll-timeout] [-h|--help]\n"
+	"--address\n"
+	"-a        : remote or local ipv6 address\n"
+	"--busy\n"
+	"-b        : busy poll io_uring instead of blocking.\n"
+	"--num_pings\n"
+	"-n        : number of pings\n"
+	"--port\n"
+	"-p        : port\n"
+	"--sqpoll\n"
+	"-s        : Configure io_uring to use SQPOLL thread\n"
+	"--timeout\n"
+	"-t        : Configure NAPI busy poll timeoutn"
+	"--help\n"
+	"-h        : Display this usage message\n\n",
+	name);
+}
+
+void printError(const char *msg, int opt)
+{
+	if (msg && opt)
+		fprintf(stderr, "%s (-%c)\n", msg, printable(opt));
+}
+
+void setProcessScheduler(void)
+{
+	struct sched_param param;
+
+	param.sched_priority = sched_get_priority_max(SCHED_FIFO);
+	if (sched_setscheduler(0, SCHED_FIFO, &param) < 0)
+		fprintf(stderr, "sched_setscheduler() failed: (%d) %s\n",
+			errno, strerror(errno));
+}
+
+double diffTimespec(const struct timespec *time1, const struct timespec *time0)
+{
+	return (time1->tv_sec - time0->tv_sec)
+		+ (time1->tv_nsec - time0->tv_nsec) / 1000000000.0;
+}
+
+uint64_t encodeUserData(char type, int fd)
+{
+	return (uint32_t)fd | ((uint64_t)type << 56);
+}
+
+void decodeUserData(uint64_t data, char *type, int *fd)
+{
+	*type = data >> 56;
+	*fd   = data & 0xffffffffU;
+}
+
+const char *opTypeToStr(char type)
+{
+	const char *res;
+
+	switch (type) {
+	case IOURING_RECV:
+		res = "IOURING_RECV";
+		break;
+	case IOURING_SEND:
+		res = "IOURING_SEND";
+		break;
+	case IOURING_RECVMSG:
+		res = "IOURING_RECVMSG";
+		break;
+	case IOURING_SENDMSG:
+		res = "IOURING_SENDMSG";
+		break;
+	default:
+		res = "Unknown";
+	}
+
+	return res;
+}
+
+void reportNapi(struct ctx *ctx)
+{
+	unsigned int napi_id = 0;
+	socklen_t len = sizeof(napi_id);
+
+	getsockopt(ctx->sockfd, SOL_SOCKET, SO_INCOMING_NAPI_ID, &napi_id, &len);
+	if (napi_id)
+		printf(" napi id: %d\n", napi_id);
+	else
+		printf(" unassigned napi id\n");
+
+	ctx->napi_check = true;
+}
+
+void sendPing(struct ctx *ctx)
+{
+	struct io_uring_sqe *sqe = io_uring_get_sqe(&ctx->ring);
+
+	clock_gettime(CLOCK_REALTIME, (struct timespec *)ctx->buffer);
+
+	io_uring_prep_send(sqe, ctx->sockfd, ctx->buffer, sizeof(struct timespec), 0);
+	sqe->user_data = encodeUserData(IOURING_SEND, ctx->sockfd);
+}
+
+void receivePing(struct ctx *ctx)
+{
+	struct io_uring_sqe *sqe = io_uring_get_sqe(&ctx->ring);
+
+	io_uring_prep_recv(sqe, ctx->sockfd, ctx->buffer, MAXBUFLEN, 0);
+	sqe->user_data = encodeUserData(IOURING_RECV, ctx->sockfd);
+}
+
+void recordRTT(struct ctx *ctx)
+{
+    struct timespec startTs = ctx->ts;
+
+    // Send next ping.
+    sendPing(ctx);
+
+    // Store round-trip time.
+    ctx->rtt[ctx->rtt_index] = diffTimespec(&ctx->ts, &startTs);
+    ctx->rtt_index++;
+}
+
+void printStats(struct ctx *ctx)
+{
+	double minRTT    = DBL_MAX;
+	double maxRTT    = 0.0;
+	double avgRTT    = 0.0;
+	double stddevRTT = 0.0;
+
+	// Calculate min, max, avg.
+	for (int i = 0; i < ctx->rtt_index; i++) {
+		if (ctx->rtt[i] < minRTT)
+			minRTT = ctx->rtt[i];
+		if (ctx->rtt[i] > maxRTT)
+			maxRTT = ctx->rtt[i];
+
+        	avgRTT += ctx->rtt[i];
+	}
+	avgRTT /= ctx->rtt_index;
+
+	// Calculate stddev.
+	for (int i = 0; i < ctx->rtt_index; i++)
+		stddevRTT += fabs(ctx->rtt[i] - avgRTT);
+	stddevRTT /= ctx->rtt_index;
+
+	fprintf(stdout, " rtt(us) min/avg/max/mdev = %.3f/%.3f/%.3f/%.3f\n",
+		minRTT * 1000000, avgRTT * 1000000, maxRTT * 1000000, stddevRTT * 1000000);
+}
+
+void completion(struct ctx *ctx, struct io_uring_cqe *cqe)
+{
+	char type;
+	int  fd;
+	int  res = cqe->res;
+
+	decodeUserData(cqe->user_data, &type, &fd);
+	if (res < 0) {
+		fprintf(stderr, "unexpected %s failure: (%d) %s\n",
+			opTypeToStr(type), -res, strerror(-res));
+		abort();
+	}
+
+	switch (type) {
+	case IOURING_SEND:
+		receivePing(ctx);
+		break;
+	case IOURING_RECV:
+		if (res != sizeof(struct timespec)) {
+			fprintf(stderr, "unexpected ping reply len: %d\n", res);
+			abort();
+		}
+
+		if (!ctx->napi_check) {
+			reportNapi(ctx);
+			sendPing(ctx);
+		} else {
+			recordRTT(ctx);
+		}
+
+		--ctx->num_pings;
+		break;
+
+	default:
+		fprintf(stderr, "unexpected %s completion\n",
+			opTypeToStr(type));
+		abort();
+		break;
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	struct ctx       ctx;
+	struct options   opt;
+	struct __kernel_timespec *tsPtr;
+	struct __kernel_timespec ts;
+	struct io_uring_params params;
+	int flag;    
+
+	memset(&opt, 0, sizeof(struct options));
+
+	// Process flags.
+	while ((flag = getopt_long(argc, argv, ":hsba:n:p:t:", longopts, NULL)) != -1) {
+		switch (flag) {
+		case 'a':
+			strcpy(opt.addr, optarg);
+			break;
+		case 'b':
+			opt.busy_loop = true;
+			break;
+		case 'h':
+			printUsage(argv[0]);
+			exit(0);
+			break;
+		case 'n':
+			opt.num_pings = atoi(optarg) + 1;
+			break;
+		case 'p':
+			strcpy(opt.port, optarg);
+			break;
+		case 's':
+                	opt.sq_poll = true;
+			break;
+		case 't':
+			opt.timeout = atoi(optarg);
+			break;
+		case ':':
+			printError("Missing argument", optopt);
+			printUsage(argv[0]);
+			exit(-1);
+			break;
+		case '?':
+			printError("Unrecognized option", optopt);
+			printUsage(argv[0]);
+			exit(-1);
+			break;
+
+		default:
+			fprintf(stderr, "Fatal: Unexpected case in CmdLineProcessor switch()\n");
+			exit(-1);
+			break;
+		}
+	}
+
+	if (strlen(opt.addr) == 0) {
+		fprintf(stderr, "address option is mandatory\n");
+		printUsage(argv[0]);
+		exit(T_EXIT_FAIL);
+	}
+
+	ctx.saddr.sin6_port   = htons(atoi(opt.port));
+	ctx.saddr.sin6_family = AF_INET6;
+
+	if (inet_pton(AF_INET6, opt.addr, &ctx.saddr.sin6_addr) <= 0) {
+        	fprintf(stderr, "inet_pton error for %s\n", optarg);
+		printUsage(argv[0]);
+		exit(T_EXIT_FAIL);
+        }
+
+	// Connect to server.
+	fprintf(stdout, "Connecting to %s... (port=%s) to send %d pings\n", opt.addr, opt.port, opt.num_pings - 1);
+
+	if ((ctx.sockfd = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
+        	fprintf(stderr, "socket() failed: (%d) %s\n", errno, strerror(errno));
+        	exit(T_EXIT_FAIL);
+	}
+
+	if (connect(ctx.sockfd, (struct sockaddr *)&ctx.saddr, sizeof(struct sockaddr_in6)) < 0) {
+		fprintf(stderr, "connect() failed: (%d) %s\n", errno, strerror(errno));
+		exit(T_EXIT_FAIL);
+	}
+
+	// Setup ring.
+	memset(&params, 0, sizeof(params));
+	memset(&ts, 0, sizeof(ts));
+
+	if (opt.sq_poll) {
+		params.flags = IORING_SETUP_SQPOLL;
+		params.sq_thread_idle = 50;
+	}
+
+	if (io_uring_queue_init_params(RINGSIZE, &ctx.ring, &params) < 0) {
+		fprintf(stderr, "io_uring_queue_init_params() failed: (%d) %s\n",
+			errno, strerror(errno));
+		exit(T_EXIT_FAIL);
+	}
+
+	if (opt.timeout)
+		io_uring_register_napi_busy_poll_timeout(&ctx.ring, opt.timeout);
+
+	if (opt.busy_loop)
+		tsPtr = &ts;
+	else
+		tsPtr = NULL;
+
+
+	// Use realtime scheduler.
+	setProcessScheduler();
+
+	// Copy payload.
+	clock_gettime(CLOCK_REALTIME, &ctx.ts);
+
+	// Setup context.
+	ctx.napi_check = false;
+	ctx.buffer_len = sizeof(struct timespec);
+	ctx.num_pings  = opt.num_pings;
+
+	ctx.rtt_index = 0;
+	ctx.rtt = (double *)malloc(sizeof(double) * opt.num_pings);
+	if (!ctx.rtt) {
+		fprintf(stderr, "Cannot allocate results array\n");
+		exit(T_EXIT_FAIL);
+	}
+
+	// Send initial message to get napi id.
+	sendPing(&ctx);
+
+        while (ctx.num_pings != 0) {
+		int res;
+		unsigned num_completed = 0;
+		unsigned head;
+		struct io_uring_cqe *cqe;
+
+		do {
+			res = io_uring_submit_and_wait_timeout(&ctx.ring, &cqe, 1, tsPtr, NULL);
+		}
+		while (res < 0 && errno == ETIME);
+
+		io_uring_for_each_cqe(&ctx.ring, head, cqe) {
+			++num_completed;
+			completion(&ctx, cqe);
+		}
+
+		if (num_completed)
+			io_uring_cq_advance(&ctx.ring, num_completed);
+	}
+
+	printStats(&ctx);
+	free(ctx.rtt);
+	io_uring_queue_exit(&ctx.ring);
+
+	// Clean up.
+	close(ctx.sockfd);
+
+	return 0;
+}
diff --git a/test/napi-busy-poll-server.c b/test/napi-busy-poll-server.c
new file mode 100644
index 0000000..535f556
--- /dev/null
+++ b/test/napi-busy-poll-server.c
@@ -0,0 +1,372 @@ 
+#include <ctype.h>
+#include <errno.h>
+#include <getopt.h>
+#include <liburing.h>
+#include <math.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <time.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <netinet/in.h>
+
+#include "helpers.h"
+
+#define MAXBUFLEN 100
+#define PORTNOLEN 10
+#define ADDRLEN   80
+#define RINGSIZE  1024
+
+#define printable(ch) (isprint((unsigned char)ch) ? ch : '#')
+
+enum {
+	IOURING_RECV,
+	IOURING_SEND,
+	IOURING_RECVMSG,
+	IOURING_SENDMSG
+};
+
+struct ctx
+{
+	struct io_uring     ring;
+	struct sockaddr_in6 saddr;
+	struct iovec        iov;
+	struct msghdr       msg;
+
+	int sockfd;
+	int buffer_len;
+	int num_pings;
+	bool napi_check;
+
+	union {
+		char buffer[MAXBUFLEN];
+		struct timespec ts;
+	};
+} ctx;
+
+struct options
+{
+	int  num_pings;
+	int  timeout;
+
+	bool listen;
+	bool sq_poll;
+	bool busy_loop;
+
+	char port[PORTNOLEN];
+	char addr[ADDRLEN];
+} options;
+
+struct option longopts[] =
+{
+	{"address"  , 1, NULL, 'a'},
+	{"busy"     , 0, NULL, 'b'},
+	{"help"     , 0, NULL, 'h'},
+	{"listen"   , 0, NULL, 'l'},
+	{"num_pings", 1, NULL, 'n'},
+	{"port"     , 1, NULL, 'p'},
+	{"sqpoll"   , 0, NULL, 's'},
+	{"timeout"  , 1, NULL, 't'},
+	{NULL       , 0, NULL,  0 }
+};
+
+void printUsage(const char *name)
+{
+	fprintf(stderr,
+        "Usage: %s [-l|--listen] [-a|--address ip_address] [-p|--port port-no] [-s|--sqpoll]"
+        " [-b|--busy] [-n|--num pings] [-t|--timeout busy-poll-timeout] [-h|--help]\n"
+	" --listen\n"
+	"-l        : Server mode\n"
+        "--address\n"
+        "-a        : remote or local ipv6 address\n"
+        "--busy\n"
+        "-b        : busy poll io_uring instead of blocking.\n"
+        "--num_pings\n"
+        "-n        : number of pings\n"
+        "--port\n"
+        "-p        : port\n"
+        "--sqpoll\n"
+        "-s        : Configure io_uring to use SQPOLL thread\n"
+        "--timeout\n"
+        "-t        : Configure NAPI busy poll timeoutn"
+        "--help\n"
+        "-h        : Display this usage message\n\n",
+	name);
+}
+
+void printError(const char *msg, int opt)
+{
+	if (msg && opt)
+		fprintf(stderr, "%s (-%c)\n", msg, printable(opt));
+}
+
+void setProcessScheduler()
+{
+	struct sched_param param;
+
+	param.sched_priority = sched_get_priority_max(SCHED_FIFO);
+	if (sched_setscheduler(0, SCHED_FIFO, &param) < 0)
+		fprintf(stderr, "sched_setscheduler() failed: (%d) %s\n",
+			errno, strerror(errno));
+}
+
+uint64_t encodeUserData(char type, int fd)
+{
+	return (uint32_t)fd | ((__u64)type << 56);
+}
+
+void decodeUserData(uint64_t data, char *type, int *fd)
+{
+	*type = data >> 56;
+	*fd   = data & 0xffffffffU;
+}
+
+const char *opTypeToStr(char type)
+{
+	const char *res;
+
+	switch (type) {
+	case IOURING_RECV:
+		res = "IOURING_RECV";
+		break;
+	case IOURING_SEND:
+		res = "IOURING_SEND";
+		break;
+	case IOURING_RECVMSG:
+		res = "IOURING_RECVMSG";
+		break;
+	case IOURING_SENDMSG:
+		res = "IOURING_SENDMSG";
+		break;
+	default:
+		res = "Unknown";
+	}
+
+	return res;
+}
+
+void reportNapi(struct ctx *ctx)
+{
+	unsigned int napi_id = 0;
+	socklen_t len = sizeof(napi_id);
+
+	getsockopt(ctx->sockfd, SOL_SOCKET, SO_INCOMING_NAPI_ID, &napi_id, &len);
+	if (napi_id)
+		printf(" napi id: %d\n", napi_id);
+	else
+		printf(" unassigned napi id\n");
+
+	ctx->napi_check = true;
+}
+
+void sendPing(struct ctx *ctx)
+{
+
+	struct io_uring_sqe *sqe = io_uring_get_sqe(&ctx->ring);
+
+	io_uring_prep_sendmsg(sqe, ctx->sockfd, &ctx->msg, 0);
+	sqe->user_data = encodeUserData(IOURING_SENDMSG, ctx->sockfd);
+}
+
+void receivePing(struct ctx *ctx)
+{
+	bzero(&ctx->msg, sizeof(struct msghdr));
+	ctx->msg.msg_name    = &ctx->saddr;
+	ctx->msg.msg_namelen = sizeof(struct sockaddr_in6);
+	ctx->iov.iov_base    = ctx->buffer;
+	ctx->iov.iov_len     = MAXBUFLEN;
+	ctx->msg.msg_iov     = &ctx->iov;
+	ctx->msg.msg_iovlen  = 1;
+
+	struct io_uring_sqe *sqe = io_uring_get_sqe(&ctx->ring);
+	io_uring_prep_recvmsg(sqe, ctx->sockfd, &ctx->msg, 0);
+	sqe->user_data = encodeUserData(IOURING_RECVMSG, ctx->sockfd);
+}
+
+void completion(struct ctx *ctx, struct io_uring_cqe *cqe)
+{
+	char type;
+	int  fd;
+	int  res = cqe->res;
+
+	decodeUserData(cqe->user_data, &type, &fd);
+	if (res < 0) {
+		fprintf(stderr, "unexpected %s failure: (%d) %s\n",
+			opTypeToStr(type), -res, strerror(-res));
+		abort();
+	}
+
+	switch (type) {
+	case IOURING_SENDMSG:
+		receivePing(ctx);
+		--ctx->num_pings;
+		break;
+	case IOURING_RECVMSG:
+		ctx->iov.iov_len = res;
+		sendPing(ctx);
+		if (!ctx->napi_check)
+			reportNapi(ctx);
+		break;
+	default:
+		fprintf(stderr, "unexpected %s completion\n",
+			opTypeToStr(type));
+		abort();
+		break;
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	int flag;    
+	struct ctx       ctx;
+	struct options   opt;
+	struct __kernel_timespec *tsPtr;
+	struct __kernel_timespec ts;
+	struct io_uring_params params;
+
+	memset(&opt, 0, sizeof(struct options));
+
+	// Process flags.
+	while ((flag = getopt_long(argc, argv, ":lhsba:n:p:t:", longopts, NULL)) != -1) {
+		switch (flag) {
+		case 'a':
+			strcpy(opt.addr, optarg);
+			break;
+		case 'b':
+			opt.busy_loop = true;
+			break;
+		case 'h':
+			printUsage(argv[0]);
+			exit(0);
+			break;
+		case 'l':
+			opt.listen = true;
+			break;
+		case 'n':
+			opt.num_pings = atoi(optarg) + 1;
+			break;
+		case 'p':
+			strcpy(opt.port, optarg);
+			break;
+		case 's':
+                	opt.sq_poll = true;
+			break;
+		case 't':
+			opt.timeout = atoi(optarg);
+			break;
+		case ':':
+			printError("Missing argument", optopt);
+			printUsage(argv[0]);
+			exit(-1);
+			break;
+		case '?':
+			printError("Unrecognized option", optopt);
+			printUsage(argv[0]);
+			exit(-1);
+			break;
+
+		default:
+			fprintf(stderr, "Fatal: Unexpected case in CmdLineProcessor switch()\n");
+			exit(-1);
+			break;
+		}
+	}
+
+	if (strlen(opt.addr) == 0) {
+		fprintf(stderr, "address option is mandatory\n");
+		printUsage(argv[0]);
+		exit(T_EXIT_FAIL);
+	}
+
+	ctx.saddr.sin6_port   = htons(atoi(opt.port));
+	ctx.saddr.sin6_family = AF_INET6;
+
+	if (inet_pton(AF_INET6, opt.addr, &ctx.saddr.sin6_addr) <= 0) {
+        	fprintf(stderr, "inet_pton error for %s\n", optarg);
+		printUsage(argv[0]);
+		exit(T_EXIT_FAIL);
+        }
+
+	// Connect to server.
+	fprintf(stdout, "Listening %s : %s...\n", opt.addr, opt.port);
+
+	if ((ctx.sockfd = socket(AF_INET6, SOCK_DGRAM, 0)) < 0) {
+        	fprintf(stderr, "socket() failed: (%d) %s\n", errno, strerror(errno));
+        	exit(T_EXIT_FAIL);
+	}
+
+	if (bind(ctx.sockfd, (struct sockaddr *)&ctx.saddr, sizeof(struct sockaddr_in6)) < 0) {
+		fprintf(stderr, "bind() failed: (%d) %s\n", errno, strerror(errno));
+		exit(T_EXIT_FAIL);
+	}
+
+	// Setup ring.
+	memset(&params, 0, sizeof(params));
+	memset(&ts, 0, sizeof(ts));
+
+	if (opt.sq_poll) {
+		params.flags = IORING_SETUP_SQPOLL;
+		params.sq_thread_idle = 50;
+	}
+
+	if (io_uring_queue_init_params(RINGSIZE, &ctx.ring, &params) < 0) {
+		fprintf(stderr, "io_uring_queue_init_params() failed: (%d) %s\n",
+			errno, strerror(errno));
+		exit(T_EXIT_FAIL);
+	}
+
+	if (opt.timeout)
+		io_uring_register_napi_busy_poll_timeout(&ctx.ring, opt.timeout);
+
+	if (opt.busy_loop)
+		tsPtr = &ts;
+	else
+		tsPtr = NULL;
+
+
+	// Use realtime scheduler.
+	setProcessScheduler();
+
+	// Copy payload.
+	clock_gettime(CLOCK_REALTIME, &ctx.ts);
+
+	// Setup context.
+	ctx.napi_check = false;
+	ctx.buffer_len = sizeof(struct timespec);
+	ctx.num_pings  = opt.num_pings;
+
+	// Receive initial message to get napi id.
+	receivePing(&ctx);
+
+        while (ctx.num_pings != 0) {
+		int res;
+		unsigned int num_completed = 0;
+		unsigned int head;
+		struct io_uring_cqe *cqe;
+
+		do {
+			res = io_uring_submit_and_wait_timeout(&ctx.ring, &cqe, 1, tsPtr, NULL);
+		}
+		while (res < 0 && errno == ETIME);
+
+		io_uring_for_each_cqe(&ctx.ring, head, cqe) {
+			++num_completed;
+			completion(&ctx, cqe);
+		}
+
+		if (num_completed) {
+			io_uring_cq_advance(&ctx.ring, num_completed);
+		}
+	}
+
+	// Clean up.
+	io_uring_queue_exit(&ctx.ring);
+	close(ctx.sockfd);
+
+	return 0;
+}