Messages in this thread | | | Date | Tue, 23 Jun 1998 17:47:06 +0300 | From | "Harvey J. Stein" <> | Subject | linux/alpha 2.0.30 - high uptime = hosed machine? |
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I've been seeing some occasionally strange behavior under linux/alpha (kernel 2.0.30, rh 4.2 + misc patches).
1. Sometimes update seems to start sucking up lots of CPU:
USER PID %CPU %MEM SIZE RSS TTY STAT START TIME COMMAND root 4372 99.9 0.2 1960 360 ? S 23:22 14:30 update (bdflush)
2. After a system has been running for a long time, it seems like hdparm reports much slower cache read times than after a reboot:
Before reboot:
blaster# /sbin/hdparm -Tt /dev/sda
/dev/sda: Timing buffer-cache reads: 32 MB in 0.53 seconds =60.38 MB/sec Timing buffered disk reads: 16 MB in 1.22 seconds =13.11 MB/sec
After reboot:
blaster# /sbin/hdparm -Tt /dev/sda
/dev/sda: Timing buffer-cache reads: 32 MB in 0.26 seconds =121.43 MB/sec Timing buffered disk reads: 16 MB in 1.18 seconds =13.54 MB/sec
Performance seems to be generally down.
3. After running for a long time, when running a couple of big jobs the machine seized up. From the noise the disk was making, it seemed like it was trying to swap to free memory, but was unable. Shift-scroll-lock was showing 0kb free pages. I forget what it showed for the number of CLEAN/LOCKED/DIRTY buffers. I eventually had to power cycle the machine. It wouldn't respond to cntrl-alt-del, programs were seg faulting all over the place, ...
Is there a memory problem causing such things?
I heard something about memory fragmentation problems. Is this a symptom? Has it been fixed/improved in the 2.0.34? Has it been fixed/improved in the 2.1 series?
Thanks,
-- Harvey J. Stein BFM Financial Research hjstein@bfr.co.il
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