Messages in this thread | | | Subject | Re: [PATCH 0/3] Enable multiple MSI feature in pSeries | From | Michael Ellerman <> | Date | Mon, 04 Feb 2013 16:56:15 +1100 |
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On Mon, 2013-02-04 at 11:49 +0800, Mike Qiu wrote: > > On Tue, 2013-01-15 at 15:38 +0800, Mike Qiu wrote: > > > Currently, multiple MSI feature hasn't been enabled in pSeries, > > > These patches try to enbale this feature. > > Hi Mike, > > > > > These patches have been tested by using ipr driver, and the driver patch > > > has been made by Wen Xiong <wenxiong@linux.vnet.ibm.com>: > > So who wrote these patches? Normally we would expect the original author > > to post the patches if at all possible. > Hi Michael > > These Multiple MSI patches were wrote by myself, you know this feature > has not enabled > and it need device driver to test whether it works suitable. So I test > my patches use > Wen Xiong's ipr patches, which has been send out to the maillinglist. > > I'm the original author :)
Ah OK, sorry, that was more or less clear from your mail but I just misunderstood.
> > > [PATCH 0/7] Add support for new IBM SAS controllers > > I would like to see the full series, including the driver enablement. > Yep, but the driver patches were wrote by Wen Xiong and has been send > out.
OK, you mean this series?
http://thread.gmane.org/gmane.linux.scsi/79639
> I just use her patches to test my patches. all device support Multiple > MSI can use my feature not only IBM SAS controllers, I also test my > patches use the broadcom wireless card tg3, and also works OK.
You mean drivers/net/ethernet/broadcom/tg3.c ? I don't see where it calls pci_enable_msi_block() ?
All devices /can/ use it, but the driver needs to be updated. Currently we have two drivers that do so (in Linus' tree), plus the updated IPR.
> > > Test platform: One partition of pSeries with one cpu core(4 SMTs) and > > > RAID bus controller: IBM PCI-E IPR SAS Adapter (ASIC) in POWER7 > > > OS version: SUSE Linux Enterprise Server 11 SP2 (ppc64) with 3.8-rc3 kernel > > > > > > IRQ 21 and 22 are assigned to the ipr device which support 2 mutiple MSI. > > > > > > The test results is shown by 'cat /proc/interrups': > > > CPU0 CPU1 CPU2 CPU3 > > > 21: 6 5 5 5 XICS Level host1-0 > > > 22: 817 814 816 813 XICS Level host1-1 > > This shows that you are correctly configuring two MSIs. > > > > But the key advantage of using multiple interrupts is to distribute load > > across CPUs and improve performance. So I would like to see some > > performance numbers that show that there is a real benefit for all the > > extra complexity in the code.
> Yes, the system just has suport two MSIs. Anyway, I will try to do > some proformance test, to show the real benefit. > But actually it needs the driver to do so. As the data show above, it > seems there is some problems in use the interrupt, the irq 21 use few, > most use 22, I will discuss with the driver author to see why and if > she fixed, I will give out the proformance result.
Yeah that would be good.
I really dislike that we have a separate API for multi-MSI vs MSI-X, and pci_enable_msi_block() also pushes the contiguous power-of-2 allocation into the irq domain layer, which is unpleasant. So if we really must do multi-MSI I would like to do it differently.
cheers
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