Running the redhat 7.3 supplied 2.4.18-5smp kernel, and before that the
redhat 7.2 supplied 2.4.9-31 kernel, I notice that I now get worse
interactive performance when the machine is doing a lot of disk io. Using
iostat/vmstat I see that there is not a lot of activity going on on the
system drive, but rather on the drives containing a lot of files which are
accessed/downloaded (web and ftp file serving).
I interpret this as that the files being service are being cached and the
caching of the mostly used files (on the system drive) is being thrown
out. Most of these files on the file-drives are only sent once and
therefore there is no use in caching them.
Is there some way of setting that the kernel can only use so much memory
to cache a specific drives content, or that a certain drive gets at least
X amount of megs to cache its contents?
I have over 1 gig of memory and user processes usually don't use that much
memory:
total used free shared buffers cached
Mem: 1160264 1150424 9840 0 66820 964292
-/+ buffers/cache: 119312 1040952
Swap: 4427928 30680 4397248
I would therefore like the system drive to always use say 128M or 256M for
buffering it's contents, or as an alternative, say that my file drives
cannot use more than 256M altogether for caching.
Is there a knob to do this, if not, is it anything that might be
implemented in the future? I have read the tuning page
<http://people.redhat.com/alikins/system_tuning.html#fs> and changed my
bdflush settings accordingly but that didn't do much difference as far as
I can see.
Btw, file serving performance is no problem, that works great, I can
transfer 15-20Megabyte/s using my Netgear 622T card.
The 2.4.9 kernel seemed to have a better interactive performance on the
same load at the price of raw performance. I got slightly better
fileserving performance after upgrading to 2.4.18, but the interactive
performance is much worse.
Any help appreciated.
-- Mikael Abrahamsson email: swmike@swm.pp.se- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sun Jun 23 2002 - 22:00:26 EST