On Mon, Feb 06, 2023 at 07:06:32AM +0000, Arseniy Krasnov wrote:
To use this option pass '--zc' parameter:

--zerocopy or --zero-copy maybe better follow what we did with the other parameters :-)


./vsock_perf --zc --sender <cid> --port <port> --bytes <bytes to send>

With this option MSG_ZEROCOPY flag will be passed to the 'send()' call.

Signed-off-by: Arseniy Krasnov <avkras...@sberdevices.ru>
---
tools/testing/vsock/vsock_perf.c | 127 +++++++++++++++++++++++++++++--
1 file changed, 120 insertions(+), 7 deletions(-)

diff --git a/tools/testing/vsock/vsock_perf.c b/tools/testing/vsock/vsock_perf.c
index a72520338f84..1d435be9b48e 100644
--- a/tools/testing/vsock/vsock_perf.c
+++ b/tools/testing/vsock/vsock_perf.c
@@ -18,6 +18,8 @@
#include <poll.h>
#include <sys/socket.h>
#include <linux/vm_sockets.h>
+#include <sys/mman.h>
+#include <linux/errqueue.h>

#define DEFAULT_BUF_SIZE_BYTES  (128 * 1024)
#define DEFAULT_TO_SEND_BYTES   (64 * 1024)
@@ -28,9 +30,14 @@
#define BYTES_PER_GB            (1024 * 1024 * 1024ULL)
#define NSEC_PER_SEC            (1000000000ULL)

+#ifndef SOL_VSOCK
+#define SOL_VSOCK 287
+#endif

I thought we use the current kernel headers when we compile the tests,
do we need to fix something in the makefile?

+
static unsigned int port = DEFAULT_PORT;
static unsigned long buf_size_bytes = DEFAULT_BUF_SIZE_BYTES;
static unsigned long vsock_buf_bytes = DEFAULT_VSOCK_BUF_BYTES;
+static bool zerocopy;

static void error(const char *s)
{
@@ -247,15 +254,74 @@ static void run_receiver(unsigned long rcvlowat_bytes)
        close(fd);
}

+static void recv_completion(int fd)
+{
+       struct sock_extended_err *serr;
+       char cmsg_data[128];
+       struct cmsghdr *cm;
+       struct msghdr msg;
+       int ret;
+
+       msg.msg_control = cmsg_data;
+       msg.msg_controllen = sizeof(cmsg_data);
+
+       ret = recvmsg(fd, &msg, MSG_ERRQUEUE);
+       if (ret == -1)
+               return;
+
+       cm = CMSG_FIRSTHDR(&msg);
+       if (!cm) {
+               fprintf(stderr, "cmsg: no cmsg\n");
+               return;
+       }
+
+       if (cm->cmsg_level != SOL_VSOCK) {
+               fprintf(stderr, "cmsg: unexpected 'cmsg_level'\n");
+               return;
+       }
+
+       if (cm->cmsg_type) {
+               fprintf(stderr, "cmsg: unexpected 'cmsg_type'\n");
+               return;
+       }
+
+       serr = (void *)CMSG_DATA(cm);
+       if (serr->ee_origin != SO_EE_ORIGIN_ZEROCOPY) {
+               fprintf(stderr, "serr: wrong origin\n");
+               return;
+       }
+
+       if (serr->ee_errno) {
+               fprintf(stderr, "serr: wrong error code\n");
+               return;
+       }
+
+       if (zerocopy && (serr->ee_code & SO_EE_CODE_ZEROCOPY_COPIED))
+               fprintf(stderr, "warning: copy instead of zerocopy\n");
+}
+
+static void enable_so_zerocopy(int fd)
+{
+       int val = 1;
+
+       if (setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY, &val, sizeof(val)))
+               error("setsockopt(SO_ZEROCOPY)");
+}
+
static void run_sender(int peer_cid, unsigned long to_send_bytes)
{
        time_t tx_begin_ns;
        time_t tx_total_ns;
        size_t total_send;
+       time_t time_in_send;
        void *data;
        int fd;

-       printf("Run as sender\n");
+       if (zerocopy)
+               printf("Run as sender MSG_ZEROCOPY\n");
+       else
+               printf("Run as sender\n");
+
        printf("Connect to %i:%u\n", peer_cid, port);
        printf("Send %lu bytes\n", to_send_bytes);
        printf("TX buffer %lu bytes\n", buf_size_bytes);
@@ -265,25 +331,58 @@ static void run_sender(int peer_cid, unsigned long 
to_send_bytes)
        if (fd < 0)
                exit(EXIT_FAILURE);

-       data = malloc(buf_size_bytes);
+       if (zerocopy) {
+               enable_so_zerocopy(fd);

-       if (!data) {
-               fprintf(stderr, "'malloc()' failed\n");
-               exit(EXIT_FAILURE);
+               data = mmap(NULL, buf_size_bytes, PROT_READ | PROT_WRITE,
+                           MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+               if (data == MAP_FAILED) {
+                       perror("mmap");
+                       exit(EXIT_FAILURE);
+               }
+       } else {
+               data = malloc(buf_size_bytes);
+
+               if (!data) {
+                       fprintf(stderr, "'malloc()' failed\n");
+                       exit(EXIT_FAILURE);
+               }
        }

Eventually to simplify the code I think we can use the mmaped buffer in
both cases.


        memset(data, 0, buf_size_bytes);
        total_send = 0;
+       time_in_send = 0;
        tx_begin_ns = current_nsec();

        while (total_send < to_send_bytes) {
                ssize_t sent;
+               size_t rest_bytes;
+               time_t before;
+
+               rest_bytes = to_send_bytes - total_send;

-               sent = write(fd, data, buf_size_bytes);
+               before = current_nsec();
+               sent = send(fd, data, (rest_bytes > buf_size_bytes) ?
+                           buf_size_bytes : rest_bytes,
+                           zerocopy ? MSG_ZEROCOPY : 0);
+               time_in_send += (current_nsec() - before);

                if (sent <= 0)
                        error("write");

+               if (zerocopy) {
+                       struct pollfd fds = { 0 };
+
+                       fds.fd = fd;

Which event are we waiting for here?

+
+                       if (poll(&fds, 1, -1) < 0) {
+                               perror("poll");
+                               exit(EXIT_FAILURE);
+                       }

We need this because we use only one buffer, but if we use more than
one, we could take full advantage of zerocopy, right?

Otherwise, I don't think it's a fair comparison with non-zerocopy.

Thanks,
Stefano

+
+                       recv_completion(fd);
+               }
+
                total_send += sent;
        }

@@ -294,9 +393,14 @@ static void run_sender(int peer_cid, unsigned long 
to_send_bytes)
               get_gbps(total_send * 8, tx_total_ns));
        printf("total time in 'write()': %f sec\n",
               (float)tx_total_ns / NSEC_PER_SEC);
+       printf("time in send %f\n", (float)time_in_send / NSEC_PER_SEC);

        close(fd);
-       free(data);
+
+       if (zerocopy)
+               munmap(data, buf_size_bytes);
+       else
+               free(data);
}

static const char optstring[] = "";
@@ -336,6 +440,11 @@ static const struct option longopts[] = {
                .has_arg = required_argument,
                .val = 'R',
        },
+       {
+               .name = "zc",
+               .has_arg = no_argument,
+               .val = 'Z',
+       },
        {},
};

@@ -351,6 +460,7 @@ static void usage(void)
               "  --help                   This message\n"
               "  --sender   <cid>           Sender mode (receiver default)\n"
               "                                <cid> of the receiver to connect 
to\n"
+              "  --zc                             Enable zerocopy\n"
               "  --port     <port>          Port (default %d)\n"
               "  --bytes    <bytes>KMG              Bytes to send (default 
%d)\n"
               "  --buf-size <bytes>KMG              Data buffer size (default %d). 
In sender mode\n"
@@ -413,6 +523,9 @@ int main(int argc, char **argv)
                case 'H': /* Help. */
                        usage();
                        break;
+               case 'Z': /* Zerocopy. */
+                       zerocopy = true;
+                       break;
                default:
                        usage();
                }
--
2.25.1


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