Re: [PARPORT] Lava Parallel Accelerator
Sat, 23 Jan 1999 10:05:19 -0500 (EST)

> one thing that I was also curious about:
> By using this PCI card, did that take a lot of load off of your
> processor when you were doing your large file copy tests?

This might be a good time to remind people about the "nice" option
on all the PARIDE drivers. Nice is 0 by default, but it can be
raised to 1 or 2 to change the scheduling policy of the driver.

In essence, we have to trade off between responsiveness to the drive
and responsiveness to the user. Increasing nice shifts the balance away
from the drive - so throughput goes down.

> Right now when I am transferring huge files, my load goes up to ~2.0
> due to the io, and makes my computer almost unusable.

There are a couple of effects that can happen. One is mitigated by the
nice option. Another is a memory management issue. If you copy a lot
of data to any slow drive, your available memory can get saturated with
pages queued for the slow device. That slows down everything else until
the buffers get flushed. Using a faster interface would allow the buffers
to flush more quickly.

Grant R. Guenther

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This archive was generated by hypermail 2.0b3 on Sat 23 Jan 1999 - 10:09:19 EST