[Vm-dev] Problems with Linux VM - EPOLL

[David T. Lewis]

Thanks Ron,

On Mon, Feb 21, 2022 at 04:16:01PM -0500, Ron Teitelbaum wrote:
>  
> Hi Levente and All,
> 
> Just wanted to pass on some information about EPOLL and Linux.
> 
> We were working on sharing our applications through RFB but were having an
> issue where keyboard input created a change on the remote window but the
> changes were not showing up.  You could see the issue with a simple browser
> doing a web search on google and pressing enter.  The screen froze but if
> you clicked with a mouse or created any other event the changes showed up.
> Eliot suggested the issue could be with EPOLL not signaling the semaphore
> properly when data was available on the socket.  After Eliot created a new
> EPOLL-less linux vm the problems went away.  There does appear to be an
> issue with EPOLL on linux.
> 
> All the best,
> 
> Ron Teitelbaum

I copied this email to a new issue on GitHub at https://github.com/OpenSmalltalk/opensmalltalk-vm/issues/615

I have added a few patches related EPOLL over the last year, primarily
related to making it work with forked Squeak VM processes (#forkSqueak
from OSProcess). I am no expert here, but it makes me wonder if there
may be some additional Linux EPOLL oddities in a multithreaded Linux VM
(just guessing).

Dave