Messages in this thread | | | Date | Mon, 04 Feb 2013 14:43:13 +0800 | From | Mike Qiu <> | Subject | Re: [PATCH 0/3] Enable multiple MSI feature in pSeries |
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2013/2/4 13:56, Michael Ellerman: > 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 Yes, exactly. > > >> 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() ? Yes, I just modify the driver to support mutiple MSI. > > 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. Not all devices, just the device which support the multiple MSI by hardware, can use it > >>>> 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. Yes, but the multi-MSI must need the hardware support, it is one extend for MSI, The device may sopport MSI and multiple MSI, but not support MSI-X. for these devices, we'd better use multiple MSI to makes it more efficiency, compare with MSI.
multi-MSI just can use no more than 32 interrupts
Thanks > > cheers > >
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