Hi Robert,
Robert Schwebel wrote:
> Wolfgang,
>
> On Wed, Jan 09, 2008 at 11:51:07PM +0100, Robert Schwebel wrote:
>> Throwing in the versions from 2.6.23.3-rt5 doesn't help, the effect
>> stays the same. So I assume it is a side effect.
>
> Can you test the following patch by John Stulz (thanks to John for the quick
> help on irc!), which fixes the issues on my board:
>
> ----------8<----------
> Index: linux-2.6.24-rc5/arch/powerpc/kernel/time.c
> ===================================================================
> --- linux-2.6.24-rc5.orig/arch/powerpc/kernel/time.c
> +++ linux-2.6.24-rc5/arch/powerpc/kernel/time.c
> @@ -773,7 +773,7 @@ void update_vsyscall(struct timespec *wa
> stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
> do_div(stamp_xsec, 1000000000);
> stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
> - update_gtod(clock->cycle_last, stamp_xsec, t2x);
> + update_gtod(clock->cycle_last-clock->cycle_accumulated, stamp_xsec, t2x);
> }
>
> void update_vsyscall_tz(void)
> ----------8<----------
>
> With this patch ontop of 2.6.24-rc5-rt1 plus the board support patches
> for the phyCORE-MPC5200B-tiny, I get this result from cyclictest, again
> under "(while true; do hackbench 10; done) &" load:
>
> T: 0 ( 867) P:80 I: 10000 C: 105002 Min: 31 Act: 48 Avg: 51 Max: 92
Unfortunately, it doesn't really help on my Icecube board.
bash-3.00# ./cyclictest -n -p80 -i1000
129.85 93.18 38.05 4/45 6354
130.41 162.23 83.05 3/49 8395
T: 0 ( 4621) P:80 I:1000 C: 477097 Min: 25 Act: 64 Avg: 67 Max:
286
bash-3.00# ./hackbench 10
Time: 95.402
Could you run your cyclictest much longer?
And hackbench takes ages, already without running cyclictest:
bash-3.00# time ./hackbench 10
Time: 83.157
real 1m23.935s
user 0m5.692s
sys 1m18.240s
With a standard non-rt kernel it just takes 10 seconds.
bash-3.00# time ./hackbench 10
Time: 9.690
real 0m10.343s
user 0m0.404s
sys 0m9.928s
Is this the normal/expected behavior under -rt?
Wolfgang.
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