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    SubjectRe: SATA-performance: Linux vs. FreeBSD
    Date
    Some more info:

    :~> strace -c -T -o trace.out dd if=/dev/zero of=test.txt bs=10MB count=200

    200+0 Datensätze ein
    200+0 Datensätze aus
    2000000000 bytes (2,0 GB) copied, 52,8632 seconds, 37,8 MB/s

    test.txt:

    % time seconds usecs/call calls errors syscall
    ------ ----------- ----------- --------- --------- ----------------
    93.26 6.845265 33555 204 write
    6.41 0.470283 11757 40 18 open
    0.32 0.023687 116 205 read
    0.00 0.000149 9 16 mmap2
    0.00 0.000119 40 3 munmap
    0.00 0.000081 3 24 close
    0.00 0.000068 6 11 old_mmap
    0.00 0.000064 3 20 fstat64
    0.00 0.000040 4 10 rt_sigaction
    0.00 0.000036 12 3 madvise
    0.00 0.000014 7 2 clock_gettime
    0.00 0.000010 3 3 brk
    0.00 0.000008 8 1 _sysctl
    0.00 0.000007 7 1 1 access
    0.00 0.000006 6 1 mprotect
    0.00 0.000005 5 1 futex
    0.00 0.000004 4 1 uname
    0.00 0.000004 4 1 _llseek
    0.00 0.000003 3 1 rt_sigprocmask
    0.00 0.000003 3 1 getrlimit
    0.00 0.000003 3 1 set_thread_area
    0.00 0.000003 3 1 set_tid_address
    ------ ----------- ----------- --------- --------- ----------------
    100.00 7.339862 551 19 total

    This means, that the CPU is only 7.3 of 52.8 seconds working. This is what one
    can hear: If I run programs where the time they need is the same time as
    strace says, then I have 100% CPU load and the cpu fan starts to blow
    heavily. In the case here, the heat fan does not do anything. It looks like
    the SATA driver simply blocks the CPU while doing whatever...
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