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Message-ID: <20230216152945.qdh6vrq66pl2bfxe@sgarzare-redhat>
Date: Thu, 16 Feb 2023 16:29:45 +0100
From: Stefano Garzarella <sgarzare@...hat.com>
To: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
Cc: Stefan Hajnoczi <stefanha@...hat.com>,
"Michael S. Tsirkin" <mst@...hat.com>,
Jason Wang <jasowang@...hat.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
Krasnov Arseniy <oxffffaa@...il.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
"virtualization@...ts.linux-foundation.org"
<virtualization@...ts.linux-foundation.org>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
kernel <kernel@...rdevices.ru>
Subject: Re: [RFC PATCH v1 12/12] test/vsock: MSG_ZEROCOPY support for
vsock_perf
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 <AVKrasnov@...rdevices.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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