Messages in this thread Patch in this message | | | From | korantwork@gmail ... | Subject | [PATCH] PCI: vmd: Do not disable MSI-X remapping in VMD 28C0 controller | Date | Thu, 22 Dec 2022 15:26:03 +0800 |
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From: Xinghui Li <korantli@tencent.com>
Commit ee81ee84f873("PCI: vmd: Disable MSI-X remapping when possible") disable the vmd MSI-X remapping for optimizing pci performance.However, this feature severely negatively optimized performance in multi-disk situations.
In FIO 4K random test, we test 1 disk in the 1 CPU
when disable MSI-X remapping: read: IOPS=1183k, BW=4622MiB/s (4847MB/s)(1354GiB/300001msec) READ: bw=4622MiB/s (4847MB/s), 4622MiB/s-4622MiB/s (4847MB/s-4847MB/s), io=1354GiB (1454GB), run=300001-300001msec
When not disable MSI-X remapping: read: IOPS=1171k, BW=4572MiB/s (4795MB/s)(1340GiB/300001msec) READ: bw=4572MiB/s (4795MB/s), 4572MiB/s-4572MiB/s (4795MB/s-4795MB/s), io=1340GiB (1438GB), run=300001-300001msec
However, the bypass mode could increase the interrupts costs in CPU. We test 12 disks in the 6 CPU,
When disable MSI-X remapping: read: IOPS=562k, BW=2197MiB/s (2304MB/s)(644GiB/300001msec) READ: bw=2197MiB/s (2304MB/s), 2197MiB/s-2197MiB/s (2304MB/s-2304MB/s), io=644GiB (691GB), run=300001-300001msec
When not disable MSI-X remapping: read: IOPS=1144k, BW=4470MiB/s (4687MB/s)(1310GiB/300005msec) READ: bw=4470MiB/s (4687MB/s), 4470MiB/s-4470MiB/s (4687MB/s-4687MB/s), io=1310GiB (1406GB), run=300005-300005msec
Signed-off-by: Xinghui Li <korantli@tencent.com> --- drivers/pci/controller/vmd.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c index e06e9f4fc50f..9f6e9324d67d 100644 --- a/drivers/pci/controller/vmd.c +++ b/drivers/pci/controller/vmd.c @@ -998,8 +998,7 @@ static const struct pci_device_id vmd_ids[] = { .driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP,}, {PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_VMD_28C0), .driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW | - VMD_FEAT_HAS_BUS_RESTRICTIONS | - VMD_FEAT_CAN_BYPASS_MSI_REMAP,}, + VMD_FEAT_HAS_BUS_RESTRICTIONS,}, {PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x467f), .driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP | VMD_FEAT_HAS_BUS_RESTRICTIONS | -- 2.39.0
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