2000-11-12 12:19:28

by Pavel Machek

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Subject: Something very wrong with time fbcon and FSBR


I wanted to measure negative impact of FSBR on my system.

I did time cat /etc/termcap. I have fbcon, so it is quite slow
operation. It took 13 seconds.

Then I made system use the FSBR, and did cat /etc/termcap. It was
visually much slower, but it gave 13 seconds again. So I did the same
test again, it said:

0.00user 13.06system 13.38 (0m13.383s) elapsed 97.59%CPU

but measured with my wristwatch, it took over 50seconds!

Something is very wrong with either USB or fbcon. Okay, now I tried
without USB, it said

0.00user 12.26system 12.33 (0m12.330s) elapsed 99.44%CPU

but took 28seconds of real time. So fbcon is making your watch loose
time. Oops. Oh, and fsbr makes system run at roughly half of normal
speed. Not good, either.

PS: fsbr means we make loop in descriptors, which then means uhci
hogging the PCI bus. Would it be possible to do some nop command (send
64 bytes to nonexisting device?) as a part of loop to avoid PCI
I'm [email protected]. "In my country we have almost anarchy and I don't care."
Panos Katsaloulis describing me w.r.t. patents at [email protected]