Re: ixg(4) performances

[Stephan <stephanwib%googlemail.com@localhost>]

What is your test setup? Do you have 2 identical boxes?

Does it perform better e.g. on Linux or FreeBSD? If so, you could
check how the config registers get set by that particular OS.

2014-08-28 9:26 GMT+02:00 Emmanuel Dreyfus <manu%netbsd.org@localhost>:
> On Tue, Aug 26, 2014 at 12:57:37PM +0000, Christos Zoulas wrote:
>> >I also found this page that tackles the same problem on Linux:
>> >http://dak1n1.com/blog/7-performance-tuning-intel-10gbe
>
> It seems that page describe a slightly different model.
> Intel 82599 datasheet is available here:
> http://www.intel.fr/content/www/fr/fr/ethernet-controllers/82599-10-gbe-controller-datasheet.html
>
> No reference to MMRBC in this document, but I understand "Max Read Request
> Size" is the same thing. Page 765 tells us about register A8, bits 12-14
> that should be set to 100.
> pcictl /dev/pci5 read -d 0 -f 1 0x18 tells me the value 0x00092810
>
> I tried this command:
> pcictl /dev/pci5 write -d 0 -f 1 0x18 0x00094810
>
> Further pcictl read suggests it works as the new value is returned.
> However it gives no performance improvement. This means that I
> misunderstood what this register is about, or how to change it (byte order?).
>
> Or the performance are constrained by something unrelated. In the blog
> post cited above, the poster acheived more than 5 Gb/s before touching
> MMRBC, while I am stuck at 2,7 GB/s. Any new idea welcome.
>
> --
> Emmanuel Dreyfus
> manu%netbsd.org@localhost