@@ -106,7 +106,7 @@ AC_CHECK_DECLS([sys_siglist], [], [], [[#include <signal.h>]])
AC_CHECK_MEMBERS([struct stat.st_mtim.tv_nsec, struct stat.st_mtimensec],
[], [], [[#include <sys/stat.h>]])
AC_CHECK_MEMBERS([struct ifreq.ifr_flagshigh], [], [], [[#include <net/if.h>]])
-AC_CHECK_FUNCS([mlockall strnlen getloadavg statvfs getmntent_r])
+AC_CHECK_FUNCS([mlockall strnlen getloadavg statvfs getmntent_r sendmmsg])
AC_CHECK_HEADERS([mntent.h sys/statvfs.h linux/types.h linux/if_ether.h stdatomic.h])
AC_CHECK_HEADERS([net/if_mib.h], [], [], [[#include <sys/types.h>
#include <net/if.h>]])
@@ -1187,6 +1187,54 @@ netdev_linux_rxq_drain(struct netdev_rxq *rxq_)
}
}
+static inline int
+netdev_linux_sock_batch_send(int sock, struct msghdr *msg,
+ struct dp_packet_batch *batch)
+{
+ int error = 0;
+ ssize_t retval;
+ uint32_t resend_idx = 0;
+ struct mmsghdr *mmsg;
+ struct iovec *iov;
+
+ mmsg = xmalloc(sizeof(*mmsg) * batch->count);
+ iov = xmalloc(sizeof(*iov) * batch->count);
+
+ for (int i = 0; i < batch->count; i++) {
+ const void *data = dp_packet_data(batch->packets[i]);
+ size_t size = dp_packet_size(batch->packets[i]);
+
+ /* Truncate the packet if it is configured. */
+ size -= dp_packet_get_cutlen(batch->packets[i]);
+
+ iov[i].iov_base = CONST_CAST(void *, data);
+ iov[i].iov_len = size;
+ mmsg[i].msg_hdr = *msg;
+ mmsg[i].msg_hdr.msg_iov = &iov[i];
+ }
+
+resend_batch:
+ retval = sendmmsg(sock, mmsg + resend_idx,
+ batch->count - resend_idx, 0);
+ if (retval < 0) {
+ if (errno == EINTR) {
+ goto resend_batch;
+ }
+ /* The Linux AF_PACKET implementation never blocks waiting for
+ * room for packets, instead returning ENOBUFS. Translate this
+ * into EAGAIN for the caller. */
+ error = errno == ENOBUFS ? EAGAIN : errno;
+ } else if (retval != batch->count - resend_idx) {
+ /* Send remain packets again. */
+ resend_idx += retval;
+ goto resend_batch;
+ }
+
+ free(mmsg);
+ free(iov);
+ return error;
+}
+
/* Sends 'buffer' on 'netdev'. Returns 0 if successful, otherwise a positive
* errno value. Returns EAGAIN without blocking if the packet cannot be queued
* immediately. Returns EMSGSIZE if a partial packet was transmitted or if
@@ -1207,6 +1255,9 @@ netdev_linux_send(struct netdev *netdev_, int qid OVS_UNUSED,
struct sockaddr_ll sll;
struct msghdr msg;
if (!is_tap_netdev(netdev_)) {
+#ifdef HAVE_SENDMMSG
+ static bool try_sendmmsg = true;
+#endif
sock = af_packet_sock();
if (sock < 0) {
error = -sock;
@@ -1231,6 +1282,21 @@ netdev_linux_send(struct netdev *netdev_, int qid OVS_UNUSED,
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
+
+#ifdef HAVE_SENDMMSG
+ if (try_sendmmsg) {
+ /* Try batch sending to socket */
+ error = netdev_linux_sock_batch_send(sock, &msg, batch);
+ if (error == ENOSYS) {
+ /* Linux kernel does not implement this function */
+ try_sendmmsg = false;
+ VLOG_WARN("Linux kernel doesn't implement sendmmsg, "
+ "going to consume sendmsg");
+ } else {
+ goto check_error;
+ }
+ }
+#endif
}
/* 'i' is incremented only if there's no error */
@@ -1290,9 +1356,10 @@ netdev_linux_send(struct netdev *netdev_, int qid OVS_UNUSED,
i++;
}
+check_error:
if (error && error != EAGAIN) {
- VLOG_WARN_RL(&rl, "error sending Ethernet packet on %s: %s",
- netdev_get_name(netdev_), ovs_strerror(error));
+ VLOG_WARN_RL(&rl, "error sending Ethernet packet on %s: %s",
+ netdev_get_name(netdev_), ovs_strerror(error));
}
free_batch:
Sendmmsg can reduce cpu cycles in sending packets to kernel. Replace sendmsg with sendmmsg in function netdev_linux_send to send batch packets if sendmmsg is available. If kernel side doesn't support sendmmsg, will fallback to sendmsg. netserver |------------| | | | container | |----veth----| | | |------------| |---veth-| dpdk-ovs | netperf | | |--------------| |----dpdk----| | bare-metal | | |--------------| | | | | pnic-----------pnic Netperf was consumed to test the performance: 1)cmd:netperf -H remote-container -t UDP_STREAM -l 60 -- -m 1400 result: netserver received 2383.21Mb(sendmsg)/2551.64Mb(sendmmsg) 2)cmd:netperf -H remote-container -t UDP_STREAM -l 60 -- -m 60 result: netserver received 109.72Mb(sendmsg)/115.18Mb(sendmmsg) Sendmmsg show about 6% improvement in netperf UDP testing. Signed-off-by: Zhenyu Gao <sysugaozhenyu@gmail.com> --- configure.ac | 2 +- lib/netdev-linux.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 70 insertions(+), 3 deletions(-)