Ultra ATA card doesn't seem to provide Ultra speeds.
mh
mh at nerim.net
Thu Jul 31 19:32:17 PDT 2003
Soeren Schmidt wrote:
>It seems Buckie wrote:
>
>
>>I ran a dd:
>>dd if=/dev/ad1 of=/dev/zero ibs=8192
>>
>>OH, you need to output to /dev/null NOT /dev/zero :)
>>
>>
It doesn't matter as far as cdevsw entry for zero-device write leads
to null_write() in /usr/src/sys/dev/null.c
I was testing the memory to memory copy through a driver using /dev/null
and /dev/zero and with
dd if=/dev/zero of=/dev/null
I get till 4.2Gb/s. Is it a maximum for memory throughout + cpu
work ? (2.4GHz Laptop with SDRAM)
Varying the bs parameter from 512 to 65536, I get a linear progression
until bs=65536 (previous throughout) but the relative throughout is
lower for bs=1024. Someone could explain?
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