[ovs-dev] [PATCH 4/4] netlink-socket.c: event polling for packets on windows

Sairam Venugopal vsairam at vmware.com
Sat Sep 19 00:54:33 UTC 2015


Acked-by: Sairam Venugopal <vsairam at vmware.com>



On 9/15/15, 11:52 AM, "Nithin Raju" <nithin at vmware.com> wrote:

>Currently, we do busy-polling for packets on Windows. In this patch
>we nuke that code and schedule an event.
>
>The code has been tested for packet reads, and CPU utilization of
>ovs-vswitchd went down drastically.
>
>I'll send out the changes to get vport events to work in a seperate
>patch.
>
>Signed-off-by: Nithin Raju <nithin at vmware.com>
>---
> lib/netlink-socket.c | 27 ++++++++++++++++++---------
> 1 file changed, 18 insertions(+), 9 deletions(-)
>
>diff --git a/lib/netlink-socket.c b/lib/netlink-socket.c
>index 42eb232..35c115a 100644
>--- a/lib/netlink-socket.c
>+++ b/lib/netlink-socket.c
>@@ -1178,10 +1178,17 @@ pend_io_request(struct nl_sock *sock)
>     struct ovs_header *ovs_header;
>     struct nlmsghdr *nlmsg;
>     uint32_t seq;
>-    int retval;
>+    int retval = 0;
>     int error;
>     DWORD bytes;
>     OVERLAPPED *overlapped = CONST_CAST(OVERLAPPED *, &sock->overlapped);
>+    uint16_t cmd = OVS_CTRL_CMD_WIN_PEND_PACKET_REQ;
>+
>+    ovs_assert(sock->read_ioctl == OVS_IOCTL_READ_PACKET ||
>+               sock->read_ioctl  == OVS_IOCTL_READ_EVENT);
>+    if (sock->read_ioctl == OVS_IOCTL_READ_EVENT) {
>+        cmd = OVS_CTRL_CMD_WIN_PEND_REQ;
>+    }
> 
>     int ovs_msg_size = sizeof (struct nlmsghdr) + sizeof (struct
>genlmsghdr) +
>                                sizeof (struct ovs_header);
>@@ -1190,7 +1197,7 @@ pend_io_request(struct nl_sock *sock)
> 
>     seq = nl_sock_allocate_seq(sock, 1);
>     nl_msg_put_genlmsghdr(&request, 0, OVS_WIN_NL_CTRL_FAMILY_ID, 0,
>-                          OVS_CTRL_CMD_WIN_PEND_REQ,
>OVS_WIN_CONTROL_VERSION);
>+                          cmd, OVS_WIN_CONTROL_VERSION);
>     nlmsg = nl_msg_nlmsghdr(&request);
>     nlmsg->nlmsg_seq = seq;
>     nlmsg->nlmsg_pid = sock->pid;
>@@ -1206,13 +1213,10 @@ pend_io_request(struct nl_sock *sock)
>         if (error != ERROR_IO_INCOMPLETE && error != ERROR_IO_PENDING) {
>             VLOG_ERR("nl_sock_wait failed - %s\n",
>ovs_format_message(error));
>             retval = EINVAL;
>-            goto done;
>         }
>     } else {
>-        /* The I/O was completed synchronously */
>-        poll_immediate_wake();
>+        retval = EAGAIN;
>     }
>-    retval = 0;
> 
> done:
>     ofpbuf_uninit(&request);
>@@ -1228,10 +1232,15 @@ nl_sock_wait(const struct nl_sock *sock, short
>int events)
> {
> #ifdef _WIN32
>     if (sock->overlapped.Internal != STATUS_PENDING) {
>-        pend_io_request(CONST_CAST(struct nl_sock *, sock));
>-       /* XXX: poll_wevent_wait(sock->overlapped.hEvent); */
>+        int ret = pend_io_request(CONST_CAST(struct nl_sock *, sock));
>+        if (ret == 0) {
>+            poll_wevent_wait(sock->overlapped.hEvent);
>+        } else {
>+            poll_immediate_wake();
>+        }
>+    } else {
>+        poll_wevent_wait(sock->overlapped.hEvent);
>     }
>-    poll_immediate_wake(); /* XXX: temporary. */
> #else
>     poll_fd_wait(sock->fd, events);
> #endif
>-- 
>1.8.5.6
>
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