Some Unix benchmarks for those who are interesed

[Ivan Voras]

Fluffles wrote:

> single drive (ad6, Maxtor MaxLine III 250GB SATA/150)
>               -------Sequential Output-------- ---Sequential Input--
> --Random--
>               -Per Char- --Block--- -Rewrite-- -Per Char- --Block---
> --Seeks---
> Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU 
> /sec %CPU
>          20480 56395 42.7 55904 12.8 21497  5.9 56846 54.3 58328  8.2 
> 81.2  0.3
> 
> Here the CPU is not the bottleneck but the disk itself. CPU is AMD
> Athlon 64 3800+ (dualcore, 2.0GHz, 2x512KB cache, S939, 2x1GB DDR/400).
> Maybe you are running a patched bonnie? By the way i'm not using
> bonnie++ but the 'original' bonnie. Maybe that changes things a bit?

Yup, that the thing.

The difference is that bonnie++ goes to the kernel for every character
read or written (in the per-char benchmark) while the old bonnie allows
for buffering in libc. At least that's the theory.

While on FreeBSD bonnie++ can get around 500 KB/s on per-chr benchmark,
on Linux it can get upto 20 MB/s:
http://fsbench.netnation.com/new_hardware/2.6.0-test9/scsi/bonnie.html

>> Fromall the benchmarks i've seen and all that i've performed myself,
> i've never seen that low per char scores like you. I cannot explain it
> except maybe a *very* slow CPU or some other obscure software issue.

Any post-Pentium 1 CPU should be fast enough to saturate disk IO in DMA
mode. The question if kernel latency is a different issue :)

Here are my "bonnie" results on the same machine (gmirror "split"
balance, 2xSATA 7.5kRPM, more than fast enough Xeon CPU):

              -------Sequential Output-------- ---Sequential Input--
--Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block---
--Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU
/sec %CPU
         4096 56456 53.2 55344 13.4 19436  6.5 60606 46.3 61417 10.4
203.0  0.8


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