Phoronix Benchmarks: Waht's wrong with FreeBSD 8.0?

[Alexander Motin]

O. Hartmann wrote:
> I'm just wondering what's wrong with FreeBSD 8.0/amd64 when I read the
> Benchmarks on Phoronix.org's website. Especially FreeBSD's threaded I/O
> shows in contrast to all claims that have been to be improoved the
> opposite.

Instead of trying to compare something, I propose to look on that
numbers itself first:
- first test tells that average write latency is about 100us. But it
looks quite surprising for Laptop HDD, which has seek time of at least
several milliseconds.
- second test - a bit closer to life - 2-3ms - ok, Linux won here
slightly, as FreeBSD installation in this test had no NCQ support.
- third test - 9us per write on Linux. I am just crying.
- forth test - all OSes gave 50-80us. Probably it is just a buffer case
read time.

So most of shown cases are testing almost only file system cache
parameters. It is just insane to compare them for so different systems
with so different write-back policies.

If somebody still have questions, after some UFS parameters tuning I've
got with the same tiotest tool:
- Random Write latency - 15us,
- Random Read latency - 7us.

So who can beat my FreeBSD? :)))

What's about second test. To check possible NCQ effect I've built test
setup with new 320GB 7200RPM Seagate drive connected to Intel ICH10R
controller. I've run IMHO more reasonable benchmark/raidtest tool from
ports on whole device, to execute pregenerated random mix of 10000
random-sized (512B - 128KB) read/write requests using default ata(4)
driver and new ahci(4):
Number of READ requests: 5029.
Number of WRITE requests: 4971.
Number of bytes to transmit: 655986688.
Number of processes: 32.

The results:
ata(4) - no NCQ:
Bytes per second: 12455402
Requests per second: 189
ahci(4) - with NCQ:
Bytes per second: 19889778
Requests per second: 303

Results are repeatable up to the 4-th digit. Average time per request is
5.29ms and 3.3ms respectively, that is realistic for this drive.

So, with such difference, I believe, we will not loose this test any more.

-- 
Alexander Motin