Daniel P. Berrangé <[email protected]> wrote: > On Wed, Aug 14, 2019 at 04:02:18AM +0200, Juan Quintela wrote: >> When we have lots of channels, sometimes multifd migration fails >> with the following error: >> >> Any good ideas? > > In inet_listen_saddr() we call > > if (!listen(slisten, 1)) { > > note the second parameter sets the socket backlog, which is the max > number of pending socket connections we allow. My guess is that the > target QEMU is not accepting incoming connections quickly enough and > thus you hit the limit & the kernel starts dropping the incoming > connections. > > As a quick test, just hack this code to pass a value of 100 and see > if it makes your test reliable. If it does, then we'll need to figure > out a nice way to handle backlog instead of hardcoding it at 1.
Nice. With this change I can create 100 channels on a 4 core machine without any trouble (5 tries so far). Previously with 10 channels on the same machine failed around 50% of the time, and 100 channels failed 100% of the time. How can we proceed from here? Thanks, Juan.
