> Something/somehow it's issuing smaller IOs when using mmap? On my box, 64K reads. Using the '-' to avoid mmap it uses 128K.
The big difference I found was that the default mmap case isn't using read-ahead. So it has to wait on the disk every time. :-( Using the '-' to avoid mmap it benefits from read-ahead, but the default of 8 isn't large enough. Crank up vfs.read_max and it becomes cpu bound. (assuming using 2 disks and not limited by both disks being on the same wimpy controller) A) Should the default vfs.read_max be increased? B) Can the mmap case be fixed? What is the aledged benefit of using mmap anyway? All I've even seen are problems. _______________________________________________ freebsd-performance@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-performance To unsubscribe, send any mail to "freebsd-performance-unsubscr...@freebsd.org"
