Re: DMA transfers in 2.5.67

Chuck Ebbert (76306.1226@compuserve.com)
Wed, 16 Apr 2003 05:45:20 -0400

> Btw, I just noticed that hard disk throughput is much lower with 2.5
> than 2.4. With 2.4.21-pre5 I get ~40 MB/s, but with 2.5.67 the speed
> drops to 25-30 MB/s. Everything according to hdparm. Is it possible
> that DMA is generally slow for some reason?

I am seeing that too, with IDE hardware.

And 2.4.20aa1 is even faster:

# mount /ext3_fs
# time dd if=/ext3_fs/100MiB_file of=/dev/null bs=32k

2.4.20aa1 : 3.3 sec (exactly what I expect to see)
2.5.66 : 6.6 sec

--
 Chuck
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