From: Mike Qiu <qiudayu@linux•vnet.ibm.com>
To: Ben Hutchings <bhutchings@solarflare•com>
Cc: Michael Chan <mchan@broadcom•com>,
eilong@broadcom•com, mcarlson@broadcom•com,
zambrano@broadcom•com, jeffrey.t.kirsher@intel•com,
netdev@vger•kernel.org
Subject: Re: BCM5719(tg3) use multiple MSI with RSS
Date: Thu, 16 May 2013 10:25:32 +0800 [thread overview]
Message-ID: <5194439C.2050509@linux.vnet.ibm.com> (raw)
In-Reply-To: <1368633120.2652.11.camel@bwh-desktop.uk.solarflarecom.com>
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.
>
prev parent reply other threads:[~2013-05-16 2:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
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