Hi,
Andreas - want me to go ahead and get you some hardware to test Ben's patch in the mean time? This way we'll at least not leave it hanging until the last moment...
I will also try this with two 20-core machines connected 10G on Monday.
I measured the performace of GHC head, 7.8.3 and 7.8.3 + Ben's patch set. Server: witty 8080 -r -a -s +RTS -N<n> *1 Measurement tool: weighttp -n 100000 -c 1000 -k -t 19 http://192.168.0.1:8080/ Measurement env: two 20 core (w/o HT) machines directly connected 10G Here is result (req/s): -N<n> 1 2 4 8 16 --------------------------------------------------------- head 92,855 155,957 306,813 498,613 527,034 7.8.3 86,494 160,321 310,675 494,020 510,751 7.8.3+ben 37,608 69,376 131,686 237,783 333,946 head and 7.8.3 has almost the same performance. But I saw significant performance regression in Ben's patch set. *1 https://github.com/kazu-yamamoto/witty/blob/master/README.md P.S. - Scalability is not linear as you can see. - prefork (witty -n <n>) got much better result than Mio (witty +RTS <n>) (677,837 req/s for witty 8080 -r -a -s -n 16) --Kazu