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    SubjectRe: b44: regression in 2.6.22 (resend)
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    On Mon, 2007-06-04 at 09:09 -0700, Stephen Hemminger wrote:
    > > > I did the test with an 2.6.22-rc3-git4 kernel and the p54 driver built
    > > > external as module.
    > >
    > > Can you look at iperf to figure out, whether it does some weird timer
    > > stuff (high frequency interval timer or such) ? Either check the code or
    > > strace it.
    >
    > It is the receiver doing a tight loop doing gettimeofday/recv calls.
    >
    >
    > sendto(-1227715616, 0xc, 3085438964, 0, {...}, 3067249832) = 0
    > gettimeofday({1180973726, 981615}, NULL) = 0
    > gettimeofday({1180973726, 981751}, NULL) = 0
    > futex(0x8055c64, 0x5 /* FUTEX_??? */, 1) = 1
    > futex(0x8055c90, FUTEX_WAKE, 1) = 0
    > recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
    > gettimeofday({1180973726, 982754}, NULL) = 0
    > recv(4, "\0\0\0\0\0\0\0\1\0\0\23\211\0\0\0\0\0\0\0\0\377\377\364"..., 8192, 0) = 8192
    > gettimeofday({1180973726, 983790}, NULL) = 0

    Well, gettimeofday() is not affected by the highres code, but

    > nanosleep({0, 0}, NULL) = 0
    > nanosleep({0, 0}, NULL) = 0

    is. The nanosleep call with a relative timeout of 0 returns immediately
    with highres enabled, while it sleeps at least until the next tick
    arrives when highres is off. Are there more of those stupid sleeps in
    the code ?

    tglx


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