Duncan Coutts wrote:
On Tue, 2008-12-23 at 03:56 +0100, wman wrote:
Thanks to you all for inspiration.
My web app (which otherwise ran ok) was getting stuck while getting harassed by ab (apache-benchmark) after receiving some 800+ requests in short succession (not less, never gotten to 900, what was weird that running like 500 reqs - pause - 500 reqs ... went ok).
After compiling with -threaded and running with +RTS -N2 it handles 10k+ requests (with 10 concurrent request running at once) without missing a beat.
How about compiled with -threaded and running with just +RTS -N1 ?
I would expect the crucial thing is the -threaded not the number of cpus running Haskell code concurrently (-threaded uses a pool of OS threads to make blocking foreign calls effectively non-blocking).
Exactly - adding another virtual CPU with +RTS -N2 should never turn a deadlocked program into a responsive one (unless there are threads busy not allocating anything, that is). Cheers, Simon