Re: Network very very slow... was iSCSI and jumbo frames

[Mike Pumford <mpumford%mudcovered.org.uk@localhost>]

On 04/02/2021 23:54, RVP wrote:

> 2. Try disabling `estd'. Since iSCSI is somewhat CPU-bound also,
>     `estd' keeping the CPU freq. low will make a difference with
>     read/write throughput.
>     My CPU was always at 800MHz even when all these tests were going
>     on. Throughput increased by a few MB with the CPU speed set to max.

Another possibility is to tune the estd parameters a bit. As far as I 
can tell estd looks at TOTAL CPU consumption to decide when to ramp up.
This is based on experimentation on my 8 core system and with 1 CPU core 
maxed out it doesn't seem to be that keen to ramp up the clock rate with 
the default parameters.

I run with:

-l 12 -h 25

added to the estd_flags in rc.conf. This seems to allow estd to keep the 
CPU ramped even for a single core load. I think estd might need some 
reworking for the now hugely multi-core processors in modern systems as 
average CPU is no longer a useful way to make an optimum performance 
decision on a multi-core system.

This estd observation is based on observation of behaviour rather than 
an actual examination of the code.

Mike