On (01/29/15 14:28), Minchan Kim wrote: > > I'm still concerned about performance numbers that I see on my x86_64. > > it's not always, but mostly slower. I'll give it another try (disable > > lockdep, etc.), but if we lose 10% on average then, sorry, I'm not so > > positive about srcu change and will tend to vote for your initial commit > > that simply moved meta free() out of init_lock and left locking as is > > (lockdep warning would have been helpful there, because otherwise it > > just looked like we change code w/o any reason). > > > > what do you thunk? > > Surely I agreee with you. If it suffers from 10% performance regression, > it's absolutely no go. > > However, I believe it should be no loss because that's one of the reason > from RCU birth which should be really win in read-side lock path compared > to other locking. > > Please test it with dd or something for block-based test for removing > noise from FS. I also will test it to confirm that with real machine. > do you test with a single dd thread/process? just dd if=foo of=bar -c... or you start N `dd &' processes? for a single writer there should be no difference, no doubt. I'm more interested in multi-writer/multi-reader/mixed use cases. the options that I use are: iozone -t 3 -R -r 16K -s 60M -I +Z and -I is: -I Use VxFS VX_DIRECT, O_DIRECT,or O_DIRECTIO for all file operations with O_DIRECT I don't think there is a lot of noise, but I'll try to use different benchmarks a bit later. -ss -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>