Cached file read performance with 6.2-PRERELEASE

[Ivan Voras]

JoaoBR wrote:

> hum, look my releng_6:
> 
> # dd of=/dev/null if=/c/c1/file bs=8k
> 100000+0 records in
> 100000+0 records out
> 819200000 bytes transferred in 1.017492 secs (805116851 bytes/sec)
> # dd of=/dev/null if=/c/c1/file bs=8k
> 100000+0 records in
> 100000+0 records out
> 819200000 bytes transferred in 1.015790 secs (806465915 bytes/sec)
> # dd of=/dev/null if=/c/c1/file bs=32k
> 25000+0 records in
> 25000+0 records out
> 819200000 bytes transferred in 0.896507 secs (913768635 bytes/sec)

Similar here (RELENG_6, a fairly slow P4/2Ghz):

> dd if=file of=/dev/null bs=8k
7690+1 records in
7690+1 records out
63003776 bytes transferred in 0.086171 secs (731146977 bytes/sec)
> dd if=file of=/dev/null bs=32k
1922+1 records in
1922+1 records out
63003776 bytes transferred in 0.070524 secs (893366745 bytes/sec)