On Tue, Mar 20 2007, Davide Libenzi wrote: > > I was looking at Jens FIO stuff, and I decided to cook a quick patch for > FIO to support GUASI (Generic Userspace Asyncronous Syscall Interface): > > http://www.xmailserver.org/guasi-lib.html > > I then ran a few tests on my Dual Opteron 252 with SATA drives (sata_nv) > and 8GB of RAM. > Mind that I'm not FIO expert, like at all, but I got some interesting > results when comparing GUASI with libaio at 8/1000/10000 depths. > If I read those result correctly (Jens may help), GUASI output is more > then double the libaio one. > Lots of context switches, yes. But the throughput looks like 2+ times. > Can someone try to repeat the measures and/or spot the error? > Or tell me which other tests to run? > This is kinda a suprise for me ...
I don't know guasi at all, but libaio requires O_DIRECT to be async. I'm sure you know this, but you may not know that fio default to buffered IO so you have to tell it to use O_DIRECT :-) So try adding a --direct=1 (or --buffered=0, same thing) as an extra option when comparing depths > 1. I'll add your guasi engine, but disable it. Unfortunately fio still doesn't have a nifty configure setup, so these things are still manual... -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/