Messages in this thread | | | Date | Tue, 20 Mar 2001 12:33:25 -0500 | From | Jeremy Jackson <> | Subject | Re: UDMA 100 / PIIX4 question |
| |
Holger Lubitz wrote:
> quintaq@yahoo.co.uk wrote: > > > > On Mon, 19 Mar 2001 12:17:38 -0800 > > Tim Moore <timothymoore@bigfoot.com> wrote: > > > > > Apologies for the too brief answer. Sustained real world transfer rates > > > for the PIIX4 under ideal > > > setup conditions and a quiet bus are 14-18MB/s. > > I dare to disagree. These numbers are from an Asus P2L97-DS (Dual P2, > Intel 440LX chipset with PIIX4) with an IBM DTLA 307045:
Yes this is why I originally replied to the post... but he's not using a PIIXx at all, but the IDE chip on an Intel 815 motherboard. I'm not sure if they use the same driver , but I don't think so.
> > > /dev/hda5: > Timing buffer-cache reads: 128 MB in 1.21 seconds =105.79 MB/sec > Timing buffered disk reads: 64 MB in 2.30 seconds = 27.83 MB/sec > > /dev/hda5 is the outermost linux partition, starting at cyl 256. > > (if you don't count hdparm measurements as real world transfer rates - > linear read as measured by bonnie is 26.3 MB/s). > > > There is a Win partition - so I do not think I am at the start of the drive. > > > > Then hdparm -tT /dev/hda > > > > /dev/hda: > > Timing buffer-cache reads: 128 MB in 1.04 seconds =123.08 MB/sec > > Timing buffered disk reads: 64 MB in 4.08 seconds = 15.69 MB/sec > > Would your windows partition by any chance be at the beginning of the > disk? > hdparm speed measurements differ by filesystem (i have no idea why,
this is false. They may differ by partition, since different parts (zones) of a modern disk have different recording densities and therefore transfer rates. IBM's spec sheet says rates vary from 15MB/sec to 31MB/sec... it he's seeing 15MB/sec, maybe he should try the other end of the disk. can you verify this? try hdparm -t /dev/hda1 instead of hda5 (if those are on opposite ends of the disk)
include output of fdisk so we can see partition layout, and results of hdparm on different areas.
> > since they don't go through it - maybe some interaction with the > buffering code). > > if you are testing a windows partition, you can expect to see > significantly lower values for hdparm: > > /dev/hda1: > Timing buffer-cache reads: 128 MB in 1.65 seconds = 77.58 MB/sec > Timing buffered disk reads: 64 MB in 3.48 seconds = 18.39 MB/sec
please show us your partition table.
> > > Remarkably /dev/hda benches slightly better, even though the 64 MB read > are nearly the same as for hda1: > > /dev/hda: > Timing buffer-cache reads: 128 MB in 1.40 seconds = 91.43 MB/sec > Timing buffered disk reads: 64 MB in 3.06 seconds = 20.92 MB/sec > > I also noticed that operations on a lot of files (like scanning for all > files in a filesystem as done by updatedb) got really slow with the 2.4 > vfat fs, with a very high percentage (in the 90s) of CPU time attributed > to "system". Has anybody else noticed this?
- 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/
| |