[EMAIL PROTECTED] wrote:
Hello!
I'm experiencing extreme lags during disk writes. I have read somewhere (didn't
save the URI, sigh) that this is actually related to bad (non-existing) write
io priorities (CFQ only manages file reads).
I could imagine two quick, easy and probably quite effective ways to prevent
such lags:
1.) don't flush buffers to disk at once more than necessary.
Actually, in many cases this is just what you do want, to avoid filling
memory with buffered writes and then flushing them on time or memory runout.
Investigate the /proc/sys/vm/dirty_* values.
2.) relate CPU niceness to max write buffer fill level (ie. the point where it
gets forced to be flushed to disk -- a conservative estimate would be much
better than nothing): (100-5*nicelevel)%, ie. writes for processes having nice
level 19 are blocked/delayed until the write buffer is below 5%. That way, the
accounting is done at a higher and probably easier to access level.
Maybe I'm just talking nonsense, but nonetheless, here are my 2 cents.
Best regards,
Mark
p.s. please CC me as I'm not subscribed to this list.
--
Bill Davidsen <[EMAIL PROTECTED]>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
