* 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 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
* 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
end of thread, other threads:[~2013-05-16 2:30 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 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 is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).