On Thursday December 21st 2006 at 20:44 Kyle Moffett wrote: > I've actually also seen filesystem operation latency double or triple > if you start trying to do operations from multiple threads at once. > Suddenly the already dog-slow single-CPU operations start bouncing > caches and the Mac OS X mostly-whole-of-BSD-BKL across CPUs and it > just crawls. I can definitely see the local disk IO taking 100x > longer than the network I/O, especially with an 8-megabit internet link. The mmap() implementation on Mac OS X ate 85% percent of system time on the old version for git-index-pack. Of that time nearly all was spent on some Mach locking function. So yes the BKL like locking inside the Mach message passing seems to be the big culprit, perhaps Andy Tanenbaum can explain this on LCA 2007. <ducks> As most developers now run multicore CPU's we notice these differences even better now! ;-) -- Marco Roeland - To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html