Messages in this thread | | | Date | Sun, 6 Apr 2003 15:21:00 -0400 | From | Chuck Ebbert <> | Subject | Re: hdparm -tT reports "suspicious results" ??? |
| |
Mark Hahn wrote:
>does "PII ODP" mean a PII in an adapter that fits into a P6 socket?
It is a factory Intel PII/333 with an HSF that fits in Socket 8. With its 512K full-speed cache it makes a PPro into a half-decent machine. Too bad they're so rare...
>> /dev/hde: >> Timing buffer-cache reads: 128 MB in 2.62 seconds = 48.85 MB/sec > > hmm, slower dram and/or FSB.
No, same exact machine in _every_ way, just a different kernel. It is slow ECC EDO memory, though.
>> /dev/hde: >> Timing buffer-cache reads: 128 MB in 2.66 seconds = 48.14 MB/sec >> Timing buffered disk reads: 64 MB in 3.90 seconds = 16.41 MB/sec.> > > dram is still slow, but disk appears slower yet, so not obviously > contaminating the measurement.
..and that's 2.5 which measures much lower but doesn't seem to be that
slow (still not tested, I'm testing RAID1 patches on 2.4 now.)
> 53073H4, ecs k7s6a-pro, athlon/"1800", DDR: > /dev/hda: > Timing buffer-cache reads: 128 MB in 0.48 seconds =266.67 MB/sec > Timing buffered disk reads: 64 MB in 2.04 seconds = 31.37 MB/sec
3 x 33073H3, RAID1, Abit KT7A-RAID, Tbird 1333, PC133 SDRAM:
Personalities : [raid0] [raid1] read_ahead 24 sectors md2 : active raid1 hdg9[0] hde8[2] hda8[1] 2409600 blocks [3/3] [UUU]
2.4.21-pre6: /dev/md2: Timing buffer-cache reads: 128 MB in 0.58 seconds =220.69 MB/sec Timing buffered disk reads: 64 MB in 2.71 seconds = 23.62 MB/sec
2.4.20aa1ce1(unreleased): /dev/md2: Timing buffer-cache reads: 128 MB in 0.59 seconds =216.95 MB/sec Timing buffered disk reads: 64 MB in 1.67 seconds = 38.32 MB/sec
I have RAID1 patches that give 55% sequential IO improvements on K7 but they're not showing the same gains on the PPro (<20% so far.) Kernel, chipset, CPU and disk controller are all different, though I expected to get proportional gains on any hardware.
AFAICT hdparm says "suspicious results" when the disk speed is greater than one-half the buffer speed. I just got 51.20 and 26.34 on the PPro with my patches and the message came out again.
-- Chuck I am not a number! - 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/
| |