[lkml]   [2006]   [Nov]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: SATA Performance with Intel ICH6
    On Fri, 24 Nov 2006 15:10:11 +0100
    "Martin A. Fink" <> wrote:

    > Here some measurement results:
    > time dd if=/dev/zero bs=1M count=1000
    > results in
    > real 0m52.561s
    > user 0m0.003s
    > sys 0m7.407s
    > and strace dd... gives among other information
    > 6.84s 1004calls syscall: write
    > So I spend 45s of 52s within the kernel. Why so long?

    Profiling the kernel will tell. Preferably with oprofile, but if for some
    reason that doesn't work, with the old profiler.

    I use this:

    sudo opcontrol --stop
    sudo opcontrol --shutdown
    sudo rm -rf /var/lib/oprofile
    sudo opcontrol --vmlinux=/boot/vmlinux-$(uname -r)
    sudo opcontrol --start-daemon
    sudo opcontrol --start
    time $@
    sudo opcontrol --stop
    sudo opcontrol --shutdown
    sudo opreport -l /boot/vmlinux-$(uname -r) | head -50

    I have seen PIO and MMIO operations on PCI busses take tremendous amounts
    of time when that bus is saturated with DMA transfers. But that was back
    in the old days.
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2006-11-25 20:29    [W:0.021 / U:18.328 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site