OK thanks for the clarification.
Regarding tx ring size setting: what about if the CPU is *not* the
bottleneck (i.e., i still have cpu headroom)? i mean if i have
tx_restart_queue events when i have plenty of cpu idle i probably need to
increase the tx ring size (probably with increasing tx interrupt rate) - but
as you say i might harm the small packet throughput...
On Tue, Apr 21, 2009 at 12:17 AM, Brandeburg, Jesse <
jesse.brandeb...@intel.com> wrote:
>
>
> On Mon, 20 Apr 2009, Benzi wrote:
>
> > Flow control is disabled.
>
> okay good.
>
> > Can you explain please why *decreasing* (and not increasing) the tx ring
> > buffer will help avoiding tx_restart_queue?
>
> the memory allocation and number of cachelines/pages being accessed goes
> from 1 page (at 256 descriptors) to 2 pages (at 512 descriptors) and it
> seems that the more pages that are accessed by the transmit
> routine/hardware writeback, the slower things get.
>
> > Regarding InterruptThrottleRate, do you mean that setting it to higher
> > value may also prevent tx_restart_queue by faster tx ring cleanup?
>
> absolutely, having a higher interrupt rate (default is only 4000
> ints/second for tx) can significantly increase the number of packets that
> can be processed per second depending on a lot of factors including packet
> size and system memory speed.
>
> Jesse
>
------------------------------------------------------------------------------
Stay on top of everything new and different, both inside and
around Java (TM) technology - register by April 22, and save
$200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
300 plus technical and hands-on sessions. Register today.
Use priority code J9JMT32. http://p.sf.net/sfu/p
_______________________________________________
E1000-devel mailing list
E1000-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/e1000-devel
