On Wed, Apr 26, 2023 at 11:42:01PM +0000, Kernel.org Bugbot wrote: > Yes. I'm using using sockets for IPC. Specifically haproxy with its > SPOE protocol. Low latency is important. Normally a call (including > optional connect if a new connection is needed) will easily complete > in under 100us. So I want to set a timeout of 1ms to avoid blocking > traffic. However because this issue effectively randomly pops up, > that 1ms timeout is too low, and the issue can actually impact > multiple in-flight requests because haproxy tries to share that one > IPC connection for them all. But if I raise the timeout (and I'd have > to raise it to something like 100ms, as I've seen delays up to 47ms in > just light testing), then I run the risk of significantly impacting > traffic if there is a legitimate slowdown. While a low timeout and > the occasional failure is probably the better of the two options, > I'd prefer not to fail at all. A quick workaround for this might be to use dup2() to open a newfd that is larger than you think your process will ever use. ulimit -n is 1024 (on my system), so choosing 1023 might be a good idea. It'll waste a little memory, but ensures the fd array will never need to expand.
