Hi all,
i'm evaluating IPC on the MPC885ADS and discovered
that the context switching times seem to be quite=20
disappointing (up to 1ms). As we need to do a lot=20
of IPC later on, i'm interested bringing the time=20
down.
Therefore i wonder, if there are any known problems=20
with the MMU on 8xx and 2.4.2x which might explain=20
that?=20
Or is this the expected context switching time for=20
CPU @ 100 MHz (RAM @ 50 MHz)? Suggestions for a=20
benchmark program?
Thanks!
Peter
Hi all,
i'm evaluating IPC on the MPC885ADS and discovered
that the context switching times seem to be quite
disappointing (up to 1ms). As we need to do a lot
of IPC later on, i'm interested bringing the time
down.
Therefore i wonder, if there are any known problems
with the MMU on 8xx and 2.4.2x which might explain
that?
Maybe it would help if you gave more detail about how
you are measuring these times in your system.
I'm interested to know the answer to this myself!
Mark Chambers
I did once ran lmbench on a proprietry 850 based board running at
62/31 Mhz
using 1 16-bit dram:
Context switching - times in microseconds - smaller is better
-------------------------------------------------------------
Host OS 2p/0K 2p/16K 2p/64K 8p/16K 8p/64K 16p/16K 16p/
64K
ctxsw ctxsw ctxsw ctxsw ctxsw ctxsw
ctxsw
--------- ------------- ----- ------ ------ ------ ------ -------
-------
test Linux 2.4.25- 259.2 234.2 302.6 304.7
This is ~ 3x faster then your 100Mhz 885...
Jaap-Jan
On 15-jun-2005, at 16:55, Schaefer-Hutter, Peter wrote:
Hi all,
i'm evaluating IPC on the MPC885ADS and discovered
that the context switching times seem to be quite
disappointing (up to 1ms). As we need to do a lot
of IPC later on, i'm interested bringing the time
down.
Therefore i wonder, if there are any known problems
with the MMU on 8xx and 2.4.2x which might explain
that?
Or is this the expected context switching time for
CPU @ 100 MHz (RAM @ 50 MHz)? Suggestions for a
benchmark program?
Thanks!
Peter
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