Quoting Mike Meyer
On Mon, 07 May 2012 02:06:31 -0400 wagnerdm@seas.upenn.edu wrote:
There have been various times when I've wished I could just spawn a thread in xmonad. Just recently, for example, it was pointed out to me that the default mod+q binding starts a brand new process just to keep xmonad responsive while it recompiles the configuration file. This is silly.
Why is it silly? It's not like the overhead of starting a new process is going to be anything but noise compared to recompiling the configuration file.
Perhaps silly is the wrong word. But: Because it means any time I want to do something with X, but keep xmonad's response time snappy, I have to create a process, make sure that process is in xmonad's PATH with all the confusing debugging associated with that (some people on #xmonad actually didn't have xmonad in their $PATH!), figure out how to do IPC...
Here is a patch bundle that makes xmonad ask X to be thread-safe, and rewrites the default mod+q binding to take advantage of the new thread safety.
What's the performance hit from making X thread-safe?
There's a hit, but considering xmonad's current strategy of completely syncing its internal state with X all the time, this is the wrong place to fix a performance problem.
For that matter, if you are using Haskell threads instead of OS threads, do you need to make X thread safe? [Sorry if this is a silly question - I'm not really familiar with using Haskell threads.]
I'm fairly certain that GHC will not context-switch during an FFI call. So using green threads may be OK. But I'm also not enough of an expert to say, and this way is certainly OK. ~d