Re: [libvirt] PATCH: 6/25: Avoid event loop wakups in remote driver

When going into the call() method, we temporarily disable the event wakup callback. The call() method is already processing any async messages which arrive, so letting the main event loop wakup here is inefficient, and indeed will block the main event loop on the mutex while the main thread is in call(). We really don't want that ! remote_internal.c | 42 ++++++++++++++++++++++++++++++++++-------- 1 file changed, 34 insertions(+), 8 deletions(-) Daniel diff --git a/src/remote_internal.c b/src/remote_internal.c

+doCall (virConnectPtr conn, struct private_data *priv,

+static int +call (virConnectPtr conn, struct private_data *priv, + int flags /* if we are in virConnectOpen */, + int proc_nr, + xdrproc_t args_filter, char *args, + xdrproc_t ret_filter, char *ret) +{ + int rv; + /* + * Avoid needless wake-ups of the event loop in the + * case where this call is being made from a different + * thread than the event loop. These wake-ups would + * cause the event loop thread to be blocked on the + * mutex for the duration of the call + */ + if (priv->watch >= 0) + virEventUpdateHandle(priv->watch, 0); + + rv = doCall(conn, priv,flags, proc_nr, + args_filter, args, + ret_filter, ret); + + if (priv->watch >= 0) + virEventUpdateHandle(priv->watch, VIR_EVENT_HANDLE_READABLE);