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
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
vm-dev@lists.squeakfoundation.org