Hi Andre,
On Fri, 11 Aug 2000, Andre Hedrick wrote:
> On Fri, 11 Aug 2000, Corin Hartland-Swann wrote:
> > When I try hdparm -m -c -d1 -a, I get the following output:
> >
> > /dev/hdc:
> > setting using_dma to 1 (on)
> > HDIO_SET_DMA failed: Operation not permitted
> > multcount = 16 (on)
> > I/O support = 1 (32-bit)
> > using_dma = 0 (off)
> > readahead = 8 (on)
>
> Sheesh you have to at least turn on in the kernel at compile time to
> attempt dma.
Sorry, my fault entirely. This is the first time that I have used kernel
2.4, and I wasn't used to the menuconfig and missed the DMA options out
(they weren't enabled by default).
The revised comparison between 2.2.15 and 2.4.0-test5 are as follows:
==> 2.2.15 <==
Dir Size BlkSz Thr# Read (CPU%) Write (CPU%) Seeks (CPU%)
----- ------ ------- ---- ------------- -------------- --------------
/mnt/ 256 4096 1 27.1371 10.3% 26.7979 23.0% 146.187 0.95%
/mnt/ 256 4096 2 27.1219 10.7% 26.6606 23.2% 142.233 0.60%
/mnt/ 256 4096 4 26.9915 10.6% 26.4289 22.9% 142.789 0.50%
/mnt/ 256 4096 16 26.4320 10.5% 26.1310 23.0% 147.424 0.52%
/mnt/ 256 4096 32 25.3407 10.1% 25.6822 22.7% 150.750 0.57%
==> 2.4.0-test5 <==
Dir Size BlkSz Thr# Read (CPU%) Write (CPU%) Seeks (CPU%)
----- ------ ------- ---- ------------- -------------- --------------
/mnt/ 256 8192 1 23.4496 9.70% 24.1711 20.6% 139.941 0.88%
/mnt/ 256 8192 2 16.9398 7.53% 24.0482 20.3% 136.706 0.69%
/mnt/ 256 8192 4 15.0166 6.82% 23.7892 20.2% 139.922 0.69%
/mnt/ 256 8192 16 13.5901 6.38% 23.2326 19.4% 147.956 0.70%
/mnt/ 256 8192 32 13.3228 6.36% 22.8210 19.0% 151.544 0.73%
So we're still seeing a drop in performance with 1 thread, and still
seeing the same severe degradation 2.2.16 exhibits.
> Maybe using the chipset tuning code to get it programmed correctly,
> would get you to the average 22MB/sec that piix and drive combo will
> do.
Sorry, I don't understand this. Could you explain it to me? Will this be
a specific option on the kernel config?
Thanks,
Corin
PS Sorry about the DMA oversight.
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