Why is MySQL nearly twice as fast on Linux?

JG amd64list at jpgsworld.com
Sat May 22 09:58:24 PDT 2004


>It would be interesting if mysql is cpu-bound or disk bound in your tests 
>and if disk-bound, the relevant lines from dmesg would be appreciated.
>FreeBSD (if I remember correctly) does not do elevator on disks by default 
>while most if not all linuxen do. That makes quite a difference on 
>disk-bound loads.
>There are other things, like flush policy which behave differently by 
>default, since linux mounts filesystems asynchronously by default.
>So if you want a fair comparison, all relevant parameters should be set to 
>same, if they are not by default.
>
>Pete

I don't think this explains why the threading is messed up.

The best FreeBSD config I've got on my AMD64 64-bit hardware was
running 32-bit i386 FreeBSD with MySQL compiled with Linuxthreads.
And those results were poor compared to  Linux tests -  they were
just much higher than any other FreeBSD config.


I's been established on the other lists that threading is not being handled 
properly to begin with.
That has been the longtime crux with MySQL on FreeBSD, and why 
"Linuxthreads" has been
recommended for so long as well, no?

Also,  we see almost nearly the same results running on a single CPU as we 
do when we run SMP

  - I don't believe the HD is to blame here.






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