Ben, I am using Bas van Dijk’s usb, and I am past the -threading issue by using the latest commit.
I don’t have any easy way of making comparisons between 7.6 and 7.8 productivity, but from oscilloscope activity, I can’t see any difference. The only difference I see is the thread scheduling on 7.8 for -N1 vs -N2/4. If —sstderr gives some notion of productivity, I’ll have to do an experiment between -N1 and -N2/4. Unchartered territory for me. I’ll setup and experiment tonight. I am not familiar with strace. I’ll fix that soon. Mike On Oct 29, 2014, at 10:24 AM, Ben Gamari <bgamari.f...@gmail.com> wrote: > Michael Jones <m...@proclivis.com> writes: > >> I have a general question about thread behavior in 7.8.3 vs 7.6.X >> >> I moved from 7.6 to 7.8 and my application behaves very differently. I >> have three threads, an application thread that plots data with >> wxhaskell or sends it over a network (depends on settings), a thread >> doing usb bulk writes, and a thread doing usb bulk reads. Data is >> moved around with TChan, and TVar is used for coordination. >> > Are you using Bas van Dijk's `usb` library by any chance? If so, you > should be aware of this [1] issue. > >> When the application was compiled with 7.6, my stream of usb traffic >> was smooth. With 7.8, there are lots of delays where nothing seems to >> be running. These delays are up to 40ms, whereas with 7.6 delays were >> a 1ms or so. >> >> When I add -N2 or -N4, the 7.8 program runs fine. But on 7.6 it runs >> fine without with -N2/4. >> >> The program is compiled -O2 with profiling. The -N2/4 version uses >> more memory, but in both cases with 7.8 and with 7.6 there is no space >> leak. >> > Have you looked at the RTS's output when run with `+RTS -sstderr`? > Is productivity any different between the two tests? > >> I tired to compile and use -ls so I could take a look with >> threadscope, but the application hangs and writes no data to the file. >> The CPU fans run wild like it is in an infinite loop. >> > Oh dear, this doesn't sound good at all. Have you tried getting a > backtrace out of gdb? Usually this isn't terribly useful but in this > case since the event log is involved it might be getting stuck in the RTS > which should give a useful backtrace. If not, perhaps strace will give > some clues as to what is happening (you'll probably want to hide > SIGVTALM to improve signal/noise)? > > Cheers, > > - Ben > > > [1] https://github.com/basvandijk/usb/issues/7 _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
