em driver 6.6.6 regression

[Jack Vogel]

On 11/7/07, Igor Sysoev <is at rambler-co.ru> wrote:
> On Wed, Nov 07, 2007 at 12:18:06PM +0300, Igor Sysoev wrote:
>
> > On Fri, Oct 12, 2007 at 04:15:46PM +0400, Igor Sysoev wrote:
> >
> > > Yesterday I have cvsup'ed FreeBSD on ThinkPad T42 to RELENG_6
> > > "2007.10.10.23.59.59" and have noticed lags while playing mp3 and browsing.
> > > I have suspected new em driver, because there was no lags if wifi iwi0
> > > was used instead of em0 for network. So I had downgraded the em driver
> > > separately to 6.2.9 version, have build a kernel loadable module, and have
> > > loaded it instead of the 6.6.6 module, and the lags have disappeared.
> > >
> > > The lags appeares only if browser (Firefox, Opera) does several requests:
> > > main page, js, images. There are no lags if browser reload simple page.
> > > Also, I could not reproduce lags by other network traffic: pings, ssh, scp,
> > > downloading files. There are no lags if I compile and so on.
> > >
> > > Some additional info:
> > >
> > > The shared irq11 is used by pcm0, em0, iwi0, CardBus, USB, and acpi_video0.
> > >
> > > em0 at pci2:1:0:   class=0x020000 card=0x05491014 chip=0x101e8086 rev=0x03 hdr=0x00
> > >     vendor     = 'Intel Corporation'
> > >     device     = '82540EP Gigabit Ethernet Controller (Mobile)'
> >
> > I just cvsup'ed to the new em 6.7.2 version without FAST interrupt and
> > lags in sound and USB mouse has gone. Thank you.
>
> However, if I define EM_FAST_IRQ, then lags appear again.

So don't define it, thats why I did this :)

If you have a server class machine with MSI or MSIX then I would try
turning FAST on, but if not leave it set for what works.

Cheers,

Jack