On Wednesday 01 December 2010 16:41:38 lidong chen wrote: > I used sr-iov, give each vm 2 vf. > after apply the patch, and i found performence is the same. > > the reason is in function msix_mmio_write, mostly addr is not in mmio > range. Did you patch qemu as well? You can see it's impossible for kernel part to work alone... http://www.mail-archive.com/kvm@xxxxxxxxxxxxxxx/msg44368.html -- regards Yang, Sheng > > static int msix_mmio_write(struct kvm_io_device *this, gpa_t addr, int len, > const void *val) > { > struct kvm_assigned_dev_kernel *adev = > container_of(this, struct kvm_assigned_dev_kernel, > msix_mmio_dev); > int idx, r = 0; > unsigned long new_val = *(unsigned long *)val; > > mutex_lock(&adev->kvm->lock); > if (!msix_mmio_in_range(adev, addr, len)) { > // return here. > r = -EOPNOTSUPP; > goto out; > } > > i printk the value: > addr start end len > F004C00C F0044000 F0044030 4 > > 00:06.0 Ethernet controller: Intel Corporation Unknown device 10ed (rev 01) > Subsystem: Intel Corporation Unknown device 000c > Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- > Stepping- SERR- FastB2B- > Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- > <TAbort- <MAbort- >SERR- <PERR- > Latency: 0 > Region 0: Memory at f0040000 (32-bit, non-prefetchable) [size=16K] > Region 3: Memory at f0044000 (32-bit, non-prefetchable) [size=16K] > Capabilities: [40] MSI-X: Enable+ Mask- TabSize=3 > Vector table: BAR=3 offset=00000000 > PBA: BAR=3 offset=00002000 > > 00:07.0 Ethernet controller: Intel Corporation Unknown device 10ed (rev 01) > Subsystem: Intel Corporation Unknown device 000c > Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- > Stepping- SERR- FastB2B- > Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- > <TAbort- <MAbort- >SERR- <PERR- > Latency: 0 > Region 0: Memory at f0048000 (32-bit, non-prefetchable) [size=16K] > Region 3: Memory at f004c000 (32-bit, non-prefetchable) [size=16K] > Capabilities: [40] MSI-X: Enable+ Mask- TabSize=3 > Vector table: BAR=3 offset=00000000 > PBA: BAR=3 offset=00002000 > > > > +static bool msix_mmio_in_range(struct kvm_assigned_dev_kernel *adev, > + gpa_t addr, int len) > +{ > + gpa_t start, end; > + > + BUG_ON(adev->msix_mmio_base == 0); > + start = adev->msix_mmio_base; > + end = adev->msix_mmio_base + PCI_MSIX_ENTRY_SIZE * > + adev->msix_max_entries_nr; > + if (addr >= start && addr + len <= end) > + return true; > + > + return false; > +} > > 2010/11/30 Yang, Sheng <sheng.yang@xxxxxxxxx>: > > On Tuesday 30 November 2010 17:10:11 lidong chen wrote: > >> sr-iov also meet this problem, MSIX mask waste a lot of cpu resource. > >> > >> I test kvm with sriov, which the vf driver could not disable msix. > >> so the host os waste a lot of cpu. cpu rate of host os is 90%. > >> > >> then I test xen with sriov, there ara also a lot of vm exits caused by > >> MSIX mask. > >> but the cpu rate of xen and domain0 is less than kvm. cpu rate of xen > >> and domain0 is 60%. > >> > >> without sr-iov, the cpu rate of xen and domain0 is higher than kvm. > >> > >> so i think the problem is kvm waste more cpu resource to deal with MSIX > >> mask. and we can see how xen deal with MSIX mask. > >> > >> if this problem sloved, maybe with MSIX enabled, the performace is > >> better. > > > > Please refer to my posted patches for this issue. > > > > http://www.spinics.net/lists/kvm/msg44992.html > > > > -- > > regards > > Yang, Sheng > > > >> 2010/11/23 Avi Kivity <avi@xxxxxxxxxx>: > >> > On 11/23/2010 09:27 AM, lidong chen wrote: > >> >> can you tell me something about this problem. > >> >> thanks. > >> > > >> > Which problem? > >> > > >> > -- > >> > I have a truly marvellous patch that fixes the bug which this > >> > signature is too narrow to contain. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
