Re: [PULL 5/5] multifd: Use number of channels as listen backlog

[Wei Yang <richard.weiyang@gmail.com>]

On Fri, Oct 11, 2019 at 12:40:03PM +0200, Juan Quintela wrote:
>Wei Yang <richardw.yang@linux.intel.com> wrote:
>> On Wed, Sep 04, 2019 at 08:29:15AM +0200, Juan Quintela wrote:
>>>Reviewed-by: Daniel P. Berrang?? <berrange@redhat.com>
>>>Signed-off-by: Juan Quintela <quintela@redhat.com>
>>>---
>>> migration/socket.c | 7 ++++++-
>>> 1 file changed, 6 insertions(+), 1 deletion(-)
>>>
>>>diff --git a/migration/socket.c b/migration/socket.c
>>>index e63f5e1612..97c9efde59 100644
>>>--- a/migration/socket.c
>>>+++ b/migration/socket.c
>>>@@ -178,10 +178,15 @@ static void socket_start_incoming_migration(SocketAddress *saddr,
>>> {
>>>     QIONetListener *listener = qio_net_listener_new();
>>>     size_t i;
>>>+    int num = 1;
>>> 
>>>     qio_net_listener_set_name(listener, "migration-socket-listener");
>>> 
>>>-    if (qio_net_listener_open_sync(listener, saddr, 1, errp) < 0) {
>>>+    if (migrate_use_multifd()) {
>>>+        num = migrate_multifd_channels();
>>>+    }
>>>+
>>>+    if (qio_net_listener_open_sync(listener, saddr, num, errp) < 0) {
>>>         object_unref(OBJECT(listener));
>>>         return;
>>>     }
>>
>> My confusion is this function is called at the beginning of the program, which
>> means we didn't set multifd on or change the multifd channel parameter.
>>
>> They are the default value at this point.
>>
>> Am I right?
>
>Hi
>
>good catch!
>
>You are right.  The fix worked for me because I always use on the
>command line:
>
>--global migration.multifd-channels=10
>
>or whatever number I want to avoid typing.  I can only see two
>solutions:
>- increase the number always

You mean change default value? Then which one should we choose?

>- require "defer" when using multifd to be able to setup parameters.
>
>Any other good ideas?

Would you mind explaining more about "defer"? How this works?

>
>Thanks, Juan.
>
>PD.  I was having problem reproducing this issue because I use the
>command line for the parameter.

-- 
Wei Yang
Help you, Help me