Raúl Sánchez Siles: > Here is something I have always liked to asks but I hadn't had the > chance. The problem is that on my job PC, I use reiser over a LVM over a > SATA disk. When I have some disk intensive tasks/intervals, my system > turns not as responsive as I wish and as I think should be.
One part of the problem is crappy PC hardware :-\. Most certainly, the SATA tranfers block the PCI bus and use up parts of your memory bandwidth while transfering data, which is a bad thing. The other part (even with non-crap) - you're putting heavy load on your disk subsystem from one process. Now, if another process tries to do disk i/o, the heavy load from the other process slows it down. > In this situation, I have tried doing top on a konsole, and I find > that the field "wa" in the above part of the top report, in the middle > of "id" and "hi" raises to 80-90%. I don't know what exactly this field > means, but I bet for cpu-wait state as it is the case in disk I/O. It's the amount of time, your systems spends waiting for i/o requests to finish, and its quite normal to have 90%+ i/o wait while you're doing disk i/o. In an ideal world, the disk operation should not influence the rest of the system too much (apart from slowing down other disk i/o.) > All of this guessing yields me to the conclusion that I'm sometimes > wasting up to 90% of cpu time waiting or just doing nothing, I can't If you're not typing very, very fast (or run some seti stuff in the background all the time), your system spends nearly 100% of it's time doing nothing ;-).
