Friendly ping~ Xinghui Li <korantwork@xxxxxxxxx> 于2023年1月10日周二 20:28写道： > > Jonathan Derrick <jonathan.derrick@xxxxxxxxx> 于2023年1月10日周二 05:00写道： > > > > As the bypass mode seems to affect performance greatly depending on the specific configuration, > > it may make sense to use a moduleparam to control it > > > We found that each pcie port can mount four drives. If we only test 2 > or 1 dirve of one pcie port, > the performance of the drive performance will be normal. Also, we > observed the interruptions in different modes. > bypass: > ..... > 2022-12-28-11-39-14: 1224 181665 IR-PCI-MSI 201850948-edge nvme0q68 > 2022-12-28-11-39-14: 1179 180115 IR-PCI-MSI 201850945-edge nvme0q65 > 2022-12-28-11-39-14: RES 26743 Rescheduling interrupts > 2022-12-28-11-39-17: irqtop - IRQ : 3029, TOTAL : 2100315228, CPU : > 192, ACTIVE CPU : 192 > disable: > ...... > 2022-12-28-12-05-56: 1714 169797 IR-PCI-MSI 14155850-edge nvme1q74 > 2022-12-28-12-05-56: 1701 168753 IR-PCI-MSI 14155849-edge nvme1q73 > 2022-12-28-12-05-56: LOC 163697 Local timer interrupts > 2022-12-28-12-05-56: TLB 5465 TLB shootdowns > 2022-12-28-12-06-00: irqtop - IRQ : 3029, TOTAL : 2179022106, CPU : > 192, ACTIVE CPU : 192 > remapping: > 022-12-28-11-25-38: 283 325568 IR-PCI-MSI 24651790-edge vmd3 > 2022-12-28-11-25-38: 140 267899 IR-PCI-MSI 13117447-edge vmd1 > 2022-12-28-11-25-38: 183 265978 IR-PCI-MSI 13117490-edge vmd1 > ...... > 2022-12-28-11-25-42: irqtop - IRQ : 2109, TOTAL : 2377172002, CPU : > 192, ACTIVE CPU : 192 > > From the result it is not difficult to find, in remapping mode the > interruptions come from vmd. > While in other modes, interrupts come from nvme devices. Besides, we > found the port mounting > 4 dirves total interruptions is much fewer than the port mounting 2 or 1 drive. > NVME 8 and 9 mount in one port, other port mount 4 dirves. > > 2022-12-28-11-39-14: 2582 494635 IR-PCI-MSI 470810698-edge nvme9q74 > 2022-12-28-11-39-14: 2579 489972 IR-PCI-MSI 470810697-edge nvme9q73 > 2022-12-28-11-39-14: 2573 480024 IR-PCI-MSI 470810695-edge nvme9q71 > 2022-12-28-11-39-14: 2544 312967 IR-PCI-MSI 470286401-edge nvme8q65 > 2022-12-28-11-39-14: 2556 312229 IR-PCI-MSI 470286405-edge nvme8q69 > 2022-12-28-11-39-14: 2547 310013 IR-PCI-MSI 470286402-edge nvme8q66 > 2022-12-28-11-39-14: 2550 308993 IR-PCI-MSI 470286403-edge nvme8q67 > 2022-12-28-11-39-14: 2559 308794 IR-PCI-MSI 470286406-edge nvme8q70 > ...... > 2022-12-28-11-39-14: 1296 185773 IR-PCI-MSI 202375243-edge nvme1q75 > 2022-12-28-11-39-14: 1209 185646 IR-PCI-MSI 201850947-edge nvme0q67 > 2022-12-28-11-39-14: 1831 184151 IR-PCI-MSI 203423828-edge nvme3q84 > 2022-12-28-11-39-14: 1254 182313 IR-PCI-MSI 201850950-edge nvme0q70 > 2022-12-28-11-39-14: 1224 181665 IR-PCI-MSI 201850948-edge nvme0q68 > 2022-12-28-11-39-14: 1179 180115 IR-PCI-MSI 201850945-edge nvme0q65 > > I'd vote for it being in VMD mode (non-bypass) by default. > I speculate that the vmd controller equalizes the interrupt load and > acts like a buffer, > which improves the performance of nvme. I am not sure about my > analysis. So, I'd like > to discuss it with the community.
