Increasing GELI performance

[Pawel Jakub Dawidek]

On Mon, Jul 30, 2007 at 10:35:32PM +0200, Fluffles wrote:
> Pawel Jakub Dawidek wrote:
> >No matter how many cores/cpus you have if you run single-threaded
> >application. What you do exactly is:
> >1. Send read of 128kB.
> >2. One of geli threads picks it up, decrypts and sends it back.
> >3. Send next read of 128kB.
> >4. One of geli threads picks it up, decrypts and sends it back.
> >...
> >
> >All threads will be used when there are more threads accessing provider.
> >  
> 
> But isn't it true that the UFS filesystem utilizes read-ahead and with 
> that a multiple I/O queue depth (somewhere between 7 to 9 queued I/O's) 
> - even when using something like dd to sequentially read a file on a 
> mounted filesystem ? Then this read-ahead will cause multiple I/O 
> request coming in and geom_eli can use multiple threads to maximize I/O 
> throughput. Maybe Dominic can try playing with the "vfs.read_max" sysctl 
> variable.

You are right in general, but if you reread e-mail I was answering to,
you will see that the author was reading from/writing to GEOM provider,
not file system.

-- 
Pawel Jakub Dawidek                       http://www.wheel.pl
pjd at FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!
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