If, for example, I run four parallel loops as below, the interactive
remote performance of the system is something like, if I hold down
the <return> key so tcsh prints out a bunch of prompts, I only get
about one or two prompts printed per second on average. If one were
to move the mouse on the X console during this time, it would be
extremely jumpy. Attempting to interactively edit files is an exercise
in cursor prediction, as well.
60 noah@goodheads ~/bench % time ./loop2
69.130u 0.000s 1:09.13 100.0% 0+0k 0+0io 111pf+0w
61 noah@goodheads ~/bench % time ./loop2 & ; time ./loop2 & ; time ./loop2 & ; time ./loop2 &
[1] 506
[2] 507
[3] 508
[4] 509
62 noah@goodheads ~/bench %
[2] Done ./loop2
70.750u 0.010s 1:10.77 99.9% 0+0k 0+0io 111pf+0w
62 noah@goodheads ~/bench %
[3] Done ./loop2
71.410u 0.030s 1:11.44 100.0% 0+0k 0+0io 111pf+0w
62 noah@goodheads ~/bench %
[4] Done ./loop2
73.700u 0.000s 1:13.72 99.9% 0+0k 0+0io 111pf+0w
62 noah@goodheads ~/bench %
[1] Done ./loop2
79.520u 0.020s 1:19.55 99.9% 0+0k 0+0io 111pf+0w
62 noah@goodheads ~/bench % time ./loop2 & ; time ./loop2 & ; time ./loop2 & ; time ./loop2 & ; time ./loop2 &
[1] 511
[2] 512
[3] 513
[4] 514
[5] 515
63 noah@goodheads ~/bench %
[5] Done ./loop2
74.660u 0.020s 1:19.80 93.5% 0+0k 0+0io 111pf+0w
63 noah@goodheads ~/bench %
[4] Done ./loop2
75.380u 0.060s 1:32.68 81.3% 0+0k 0+0io 111pf+0w
63 noah@goodheads ~/bench %
[3] Done ./loop2
74.160u 0.000s 1:32.89 79.8% 0+0k 0+0io 111pf+0w
63 noah@goodheads ~/bench %
[2] Done ./loop2
74.610u 0.010s 1:34.09 79.3% 0+0k 0+0io 111pf+0w
63 noah@goodheads ~/bench %
[1] Done ./loop2
75.930u 0.060s 1:35.30 79.7% 0+0k 0+0io 111pf+0w
63 noah@goodheads ~/bench % cat loop2.C
main(){
for(signed long i=0xc0000000; i<0x7fffffff;i++)
;
}
That was compiled with no optimizations, btw.
Noah
Scott McNab wrote:
>
> Hello.
>
> Has process scheduling been changed significantly between 2.1.125 and
> 2.1.126? On my dual PII-300 the responsiveness of the machine when both
> processors are loaded seems considerably worse.
>
> Under 2.1.125 I could run 2 l3enc processes simultaneously with normal
> priority and it would not visibly disturb the X server for most
> activities.
>
> However, using 2.1.126 I find that as soon as I start these 2 processes
> the mouse cursor under X becomes very jumpy and slow to respond making
> the system unpleasant to use.
>
> I am not sure whether it is due to a change in the scheduling algorithm
> or whether there is some other problem but kswapd seems to take a lot
> more CPU cycles than previously (according to top).
>
> Has anyone else noticed similar symptoms? Please CC me in the reply as
> I'm not subscribed to this list.
>
> ------------------------------------------------------------------------
> Scott McNab Phone: +61 8 9386 0540
> Software Engineer Student Support Officer
> Research and Development Dept University Computing Services
> Fractal Graphics University of Western Australia
> http://www.fractal.csiro.au/ http://www.uwa.edu.au/
> sdm@fractal.csiro.au jedi@tartarus.uwa.edu.au
>
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