* BCM5719(tg3) use multiple MSI with RSS
@ 2013-05-15 7:56 Mike Qiu
2013-05-15 15:08 ` Michael Chan
0 siblings, 1 reply; 6+ messages in thread
From: Mike Qiu @ 2013-05-15 7:56 UTC (permalink / raw)
To: eilong, mchan, mcarlson, zambrano, jeffrey.t.kirsher; +Cc: netdev
Hi all
Currently, I need to enable multiple MSI on BCM5719 network card.
But I look in to the spec of 5719 from Broadcom, it seems
that RSS just enable with MSI-X, so I'm not sure if multiple
MSI can use RSS.
And if multiple MSI can't use RSS, how other usage of the
interrupts allocated from the system? Can they be used to
improve the performance of the network?
Thanks
Mike
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: BCM5719(tg3) use multiple MSI with RSS
2013-05-15 7:56 BCM5719(tg3) use multiple MSI with RSS Mike Qiu
@ 2013-05-15 15:08 ` Michael Chan
2013-05-15 15:52 ` Ben Hutchings
0 siblings, 1 reply; 6+ messages in thread
From: Michael Chan @ 2013-05-15 15:08 UTC (permalink / raw)
To: Mike Qiu; +Cc: eilong, mcarlson, zambrano, jeffrey.t.kirsher, netdev
On Wed, 2013-05-15 at 15:56 +0800, Mike Qiu wrote:
> Hi all
>
> Currently, I need to enable multiple MSI on BCM5719 network card.
> But I look in to the spec of 5719 from Broadcom, it seems
> that RSS just enable with MSI-X, so I'm not sure if multiple
> MSI can use RSS.
>
MSI can only support one IRQ source and cannot support RSS.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: BCM5719(tg3) use multiple MSI with RSS
2013-05-15 15:08 ` Michael Chan
@ 2013-05-15 15:52 ` Ben Hutchings
2013-05-15 16:03 ` Michael Chan
2013-05-16 2:25 ` Mike Qiu
0 siblings, 2 replies; 6+ messages in thread
From: Ben Hutchings @ 2013-05-15 15:52 UTC (permalink / raw)
To: Michael Chan
Cc: Mike Qiu, eilong, mcarlson, zambrano, jeffrey.t.kirsher, netdev
On Wed, 2013-05-15 at 08:08 -0700, Michael Chan wrote:
> On Wed, 2013-05-15 at 15:56 +0800, Mike Qiu wrote:
> > Hi all
> >
> > Currently, I need to enable multiple MSI on BCM5719 network card.
> > But I look in to the spec of 5719 from Broadcom, it seems
> > that RSS just enable with MSI-X, so I'm not sure if multiple
> > MSI can use RSS.
> >
>
> MSI can only support one IRQ source and cannot support RSS.
It is possible for an MSI capability to have multiple MSIs, but they
will use the same address and consecutive data values.
On x86, if you can find a large enough block of free IRQs on an IOAPIC,
it is possible to implement RSS this way. Linux supports this on
systems with an x2apic.
Now, maybe tg3 hardware doesn't support this (and really, why bother
when there is MSI-X?) but the option does exist.
Ben.
--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: BCM5719(tg3) use multiple MSI with RSS
2013-05-15 15:52 ` Ben Hutchings
@ 2013-05-15 16:03 ` Michael Chan
2013-05-16 2:30 ` Mike Qiu
2013-05-16 2:25 ` Mike Qiu
1 sibling, 1 reply; 6+ messages in thread
From: Michael Chan @ 2013-05-15 16:03 UTC (permalink / raw)
To: Ben Hutchings
Cc: Mike Qiu, eilong, mcarlson, zambrano, jeffrey.t.kirsher, netdev
On Wed, 2013-05-15 at 16:52 +0100, Ben Hutchings wrote:
> On Wed, 2013-05-15 at 08:08 -0700, Michael Chan wrote:
> > On Wed, 2013-05-15 at 15:56 +0800, Mike Qiu wrote:
> > > Hi all
> > >
> > > Currently, I need to enable multiple MSI on BCM5719 network card.
> > > But I look in to the spec of 5719 from Broadcom, it seems
> > > that RSS just enable with MSI-X, so I'm not sure if multiple
> > > MSI can use RSS.
> > >
> >
> > MSI can only support one IRQ source and cannot support RSS.
>
> It is possible for an MSI capability to have multiple MSIs, but they
> will use the same address and consecutive data values.
>
> On x86, if you can find a large enough block of free IRQs on an IOAPIC,
> it is possible to implement RSS this way. Linux supports this on
> systems with an x2apic.
>
> Now, maybe tg3 hardware doesn't support this (and really, why bother
> when there is MSI-X?) but the option does exist.
Yes, tg3 hardware (may be all Broadcom hardware) can only use MSI as a
replacement for INTA.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: BCM5719(tg3) use multiple MSI with RSS
2013-05-15 15:52 ` Ben Hutchings
2013-05-15 16:03 ` Michael Chan
@ 2013-05-16 2:25 ` Mike Qiu
1 sibling, 0 replies; 6+ messages in thread
From: Mike Qiu @ 2013-05-16 2:25 UTC (permalink / raw)
To: Ben Hutchings
Cc: Michael Chan, eilong, mcarlson, zambrano, jeffrey.t.kirsher,
netdev
于 2013/5/15 23:52, Ben Hutchings 写道:
> On Wed, 2013-05-15 at 08:08 -0700, Michael Chan wrote:
>> On Wed, 2013-05-15 at 15:56 +0800, Mike Qiu wrote:
>>> Hi all
>>>
>>> Currently, I need to enable multiple MSI on BCM5719 network card.
>>> But I look in to the spec of 5719 from Broadcom, it seems
>>> that RSS just enable with MSI-X, so I'm not sure if multiple
>>> MSI can use RSS.
>>>
>> MSI can only support one IRQ source and cannot support RSS.
> It is possible for an MSI capability to have multiple MSIs, but they
> will use the same address and consecutive data values.
Yes, it should be this.
> On x86, if you can find a large enough block of free IRQs on an IOAPIC,
> it is possible to implement RSS this way. Linux supports this on
> systems with an x2apic.
But, I see the tg3 spec, and it seems the RSS is just for MSI-X(and IOV).
And I try to enable RSS use multiple MSI for 4 irqs, the system
alloc 4 consecutive irqs to tg3, and each one can be test pass using
interrupt test.
But the last 3 interrupts seems not to be triggered as "cat /proc/interrups"
shows after the driver loaded. Only the first irq can be triggered for
only sometimes. The network surely not work.
> Now, maybe tg3 hardware doesn't support this (and really, why bother
> when there is MSI-X?) but the option does exist.
Actually, I try to enable the multiple MSI feature, and needs tg3 card to
support this feature. For some old PCI device, it may only support
multiple MSI
Thanks
Mike
>
> Ben.
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: BCM5719(tg3) use multiple MSI with RSS
2013-05-15 16:03 ` Michael Chan
@ 2013-05-16 2:30 ` Mike Qiu
0 siblings, 0 replies; 6+ messages in thread
From: Mike Qiu @ 2013-05-16 2:30 UTC (permalink / raw)
To: Michael Chan
Cc: Ben Hutchings, eilong, mcarlson, zambrano, jeffrey.t.kirsher,
netdev
于 2013/5/16 0:03, Michael Chan 写道:
> On Wed, 2013-05-15 at 16:52 +0100, Ben Hutchings wrote:
>> On Wed, 2013-05-15 at 08:08 -0700, Michael Chan wrote:
>>> On Wed, 2013-05-15 at 15:56 +0800, Mike Qiu wrote:
>>>> Hi all
>>>>
>>>> Currently, I need to enable multiple MSI on BCM5719 network card.
>>>> But I look in to the spec of 5719 from Broadcom, it seems
>>>> that RSS just enable with MSI-X, so I'm not sure if multiple
>>>> MSI can use RSS.
>>>>
>>> MSI can only support one IRQ source and cannot support RSS.
>> It is possible for an MSI capability to have multiple MSIs, but they
>> will use the same address and consecutive data values.
>>
>> On x86, if you can find a large enough block of free IRQs on an IOAPIC,
>> it is possible to implement RSS this way. Linux supports this on
>> systems with an x2apic.
>>
>> Now, maybe tg3 hardware doesn't support this (and really, why bother
>> when there is MSI-X?) but the option does exist.
> Yes, tg3 hardware (may be all Broadcom hardware) can only use MSI as a
> replacement for INTA.
That you mean, it can't use multiple MSI for RSS ?
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-05-16 2:30 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2013-05-15 7:56 BCM5719(tg3) use multiple MSI with RSS Mike Qiu
2013-05-15 15:08 ` Michael Chan
2013-05-15 15:52 ` Ben Hutchings
2013-05-15 16:03 ` Michael Chan
2013-05-16 2:30 ` Mike Qiu
2013-05-16 2:25 ` Mike Qiu
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