ZFS/RAIDZ and SAMBA: abyssimal performance

[Daniel Kalchev]

On Jan 4, 2013, at 4:06 PM, Fleuriot Damien <ml at my.gd> wrote:

> 
> And network cards:
> # Up a bit our intel cards parameters
> hw.em.txd=4096
> hw.em.rxd=4096
> hw.em.tx_int_delay=512
> hw.em.rx_int_delay=512
> hw.em.tx_abs_int_delay=1024
> hw.em.rx_abs_int_delay=1024
> 

I am curious why we need to manually set up these values. Especially the txd/rxd -- here are few controllers supported by the em driver that can't handle 4096 descriptors and the choice could really be made at driver attach time.. That could also permit different em interfaces in the system (using different chips) to have different settings.

My belief is the auto tuning should set things up for maximum performance, given the hardware and if someone really needs smaller queues they could just use the tunables. 

Are there drawbacks?

Daniel