drivers/vdpa/virtio_pci/vp_vdpa.c | 35 +++++++++++++++++++------------ 1 file changed, 22 insertions(+), 13 deletions(-)
When there is a ctlq and it doesn't require interrupt
callbacks,the original method of calculating vectors
wastes hardware msi or msix resources as well as system
IRQ resources.
When conducting performance testing using testpmd in the
guest os, it was found that the performance was lower compared
to directly using vfio-pci to passthrough the device
In scenarios where the virtio device in the guest os does
not utilize interrupts, the vdpa driver still configures
the hardware's msix vector. Therefore, the hardware still
sends interrupts to the host os. Because of this unnecessary
action by the hardware, hardware performance decreases, and
it also affects the performance of the host os.
Before modification:(interrupt mode)
32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
After modification:(interrupt mode)
32: 0 0 1 7 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
33: 36 0 3 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-config
Before modification:(virtio pmd mode for guest os)
32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
After modification:(virtio pmd mode for guest os)
32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-config
To verify the use of the virtio PMD mode in the guest operating
system, the following patch needs to be applied to QEMU:
https://lore.kernel.org/all/20240408073311.2049-1-yuxue.liu@jaguarmicro.com
Signed-off-by: lyx634449800 <yuxue.liu@jaguarmicro.com>
---
V3: delete unused variables and add validation records
V2: fix when allocating IRQs, scan all queues
drivers/vdpa/virtio_pci/vp_vdpa.c | 35 +++++++++++++++++++------------
1 file changed, 22 insertions(+), 13 deletions(-)
diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
index df5f4a3bccb5..cd3aeb3b8f21 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -160,22 +160,31 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
struct pci_dev *pdev = mdev->pci_dev;
int i, ret, irq;
int queues = vp_vdpa->queues;
- int vectors = queues + 1;
+ int msix_vec, allocated_vectors = 0;
- ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
- if (ret != vectors) {
+ for (i = 0; i < queues; i++) {
+ if (vp_vdpa->vring[i].cb.callback)
+ allocated_vectors++;
+ }
+ allocated_vectors = allocated_vectors + 1;
+
+ ret = pci_alloc_irq_vectors(pdev, allocated_vectors, allocated_vectors,
+ PCI_IRQ_MSIX);
+ if (ret != allocated_vectors) {
dev_err(&pdev->dev,
"vp_vdpa: fail to allocate irq vectors want %d but %d\n",
- vectors, ret);
+ allocated_vectors, ret);
return ret;
}
-
- vp_vdpa->vectors = vectors;
+ vp_vdpa->vectors = allocated_vectors;
for (i = 0; i < queues; i++) {
+ if (!vp_vdpa->vring[i].cb.callback)
+ continue;
+
snprintf(vp_vdpa->vring[i].msix_name, VP_VDPA_NAME_SIZE,
"vp-vdpa[%s]-%d\n", pci_name(pdev), i);
- irq = pci_irq_vector(pdev, i);
+ irq = pci_irq_vector(pdev, msix_vec);
ret = devm_request_irq(&pdev->dev, irq,
vp_vdpa_vq_handler,
0, vp_vdpa->vring[i].msix_name,
@@ -185,23 +194,23 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
"vp_vdpa: fail to request irq for vq %d\n", i);
goto err;
}
- vp_modern_queue_vector(mdev, i, i);
+ vp_modern_queue_vector(mdev, i, msix_vec);
vp_vdpa->vring[i].irq = irq;
+ msix_vec++;
}
snprintf(vp_vdpa->msix_name, VP_VDPA_NAME_SIZE, "vp-vdpa[%s]-config\n",
- pci_name(pdev));
- irq = pci_irq_vector(pdev, queues);
+ pci_name(pdev));
+ irq = pci_irq_vector(pdev, msix_vec);
ret = devm_request_irq(&pdev->dev, irq, vp_vdpa_config_handler, 0,
vp_vdpa->msix_name, vp_vdpa);
if (ret) {
dev_err(&pdev->dev,
- "vp_vdpa: fail to request irq for vq %d\n", i);
+ "vp_vdpa: fail to request irq for config\n");
goto err;
}
- vp_modern_config_vector(mdev, queues);
+ vp_modern_config_vector(mdev, msix_vec);
vp_vdpa->config_irq = irq;
-
return 0;
err:
vp_vdpa_free_irq(vp_vdpa);
--
2.43.0better subject:
vp_vdpa: don't allocate unused msix vectors
to make it clear it's not a bugfix.
more comments below, but most importantly this
looks like it adds a bug.
On Tue, Apr 09, 2024 at 09:49:35AM +0800, lyx634449800 wrote:
> When there is a ctlq and it doesn't require interrupt
> callbacks,the original method of calculating vectors
> wastes hardware msi or msix resources as well as system
> IRQ resources.
>
> When conducting performance testing using testpmd in the
> guest os, it was found that the performance was lower compared
> to directly using vfio-pci to passthrough the device
>
> In scenarios where the virtio device in the guest os does
> not utilize interrupts, the vdpa driver still configures
> the hardware's msix vector. Therefore, the hardware still
> sends interrupts to the host os. Because of this unnecessary
> action by the hardware, hardware performance decreases, and
> it also affects the performance of the host os.
>
> Before modification:(interrupt mode)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
> 35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
>
> After modification:(interrupt mode)
> 32: 0 0 1 7 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 36 0 3 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-config
>
> Before modification:(virtio pmd mode for guest os)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
> 35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
>
> After modification:(virtio pmd mode for guest os)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-config
>
> To verify the use of the virtio PMD mode in the guest operating
> system, the following patch needs to be applied to QEMU:
> https://lore.kernel.org/all/20240408073311.2049-1-yuxue.liu@jaguarmicro.com
>
> Signed-off-by: lyx634449800 <yuxue.liu@jaguarmicro.com>
Bad S.O.B format. Should be
Signed-off-by: Real Name <email>
> ---
>
> V3: delete unused variables and add validation records
> V2: fix when allocating IRQs, scan all queues
>
> drivers/vdpa/virtio_pci/vp_vdpa.c | 35 +++++++++++++++++++------------
> 1 file changed, 22 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> index df5f4a3bccb5..cd3aeb3b8f21 100644
> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> @@ -160,22 +160,31 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> struct pci_dev *pdev = mdev->pci_dev;
> int i, ret, irq;
> int queues = vp_vdpa->queues;
> - int vectors = queues + 1;
> + int msix_vec, allocated_vectors = 0;
I would actually call allocated_vectors -> vectors, make the patch
smaller.
>
> - ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
> - if (ret != vectors) {
> + for (i = 0; i < queues; i++) {
> + if (vp_vdpa->vring[i].cb.callback)
> + allocated_vectors++;
> + }
> + allocated_vectors = allocated_vectors + 1;
better:
allocated_vectors++; /* extra one for config */
> +
> + ret = pci_alloc_irq_vectors(pdev, allocated_vectors, allocated_vectors,
> + PCI_IRQ_MSIX);
> + if (ret != allocated_vectors) {
> dev_err(&pdev->dev,
> "vp_vdpa: fail to allocate irq vectors want %d but %d\n",
> - vectors, ret);
> + allocated_vectors, ret);
> return ret;
> }
> -
> - vp_vdpa->vectors = vectors;
> + vp_vdpa->vectors = allocated_vectors;
>
> for (i = 0; i < queues; i++) {
> + if (!vp_vdpa->vring[i].cb.callback)
> + continue;
> +
> snprintf(vp_vdpa->vring[i].msix_name, VP_VDPA_NAME_SIZE,
> "vp-vdpa[%s]-%d\n", pci_name(pdev), i);
> - irq = pci_irq_vector(pdev, i);
> + irq = pci_irq_vector(pdev, msix_vec);
using uninitialized msix_vec here?
I would expect compiler to warn about it.
pay attention to compiler warnings pls.
> ret = devm_request_irq(&pdev->dev, irq,
> vp_vdpa_vq_handler,
> 0, vp_vdpa->vring[i].msix_name,
> @@ -185,23 +194,23 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> "vp_vdpa: fail to request irq for vq %d\n", i);
> goto err;
> }
> - vp_modern_queue_vector(mdev, i, i);
> + vp_modern_queue_vector(mdev, i, msix_vec);
> vp_vdpa->vring[i].irq = irq;
> + msix_vec++;
> }
>
> snprintf(vp_vdpa->msix_name, VP_VDPA_NAME_SIZE, "vp-vdpa[%s]-config\n",
> - pci_name(pdev));
> - irq = pci_irq_vector(pdev, queues);
> + pci_name(pdev));
don't move pci_name - don't make unrelated code changes.
> + irq = pci_irq_vector(pdev, msix_vec);
> ret = devm_request_irq(&pdev->dev, irq, vp_vdpa_config_handler, 0,
> vp_vdpa->msix_name, vp_vdpa);
> if (ret) {
> dev_err(&pdev->dev,
> - "vp_vdpa: fail to request irq for vq %d\n", i);
> + "vp_vdpa: fail to request irq for config\n");
I would report ret here too.
> goto err;
> }
> - vp_modern_config_vector(mdev, queues);
> + vp_modern_config_vector(mdev, msix_vec);
> vp_vdpa->config_irq = irq;
> -
don't make unrelated code changes.
> return 0;
> err:
> vp_vdpa_free_irq(vp_vdpa);
> --
> 2.43.0
From: Yuxue Liu <yuxue.liu@jaguarmicro.com>
When there is a ctlq and it doesn't require interrupt
callbacks,the original method of calculating vectors
wastes hardware msi or msix resources as well as system
IRQ resources.
When conducting performance testing using testpmd in the
guest os, it was found that the performance was lower compared
to directly using vfio-pci to passthrough the device
In scenarios where the virtio device in the guest os does
not utilize interrupts, the vdpa driver still configures
the hardware's msix vector. Therefore, the hardware still
sends interrupts to the host os. Because of this unnecessary
action by the hardware, hardware performance decreases, and
it also affects the performance of the host os.
Before modification:(interrupt mode)
32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
After modification:(interrupt mode)
32: 0 0 1 7 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
33: 36 0 3 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-config
Before modification:(virtio pmd mode for guest os)
32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
After modification:(virtio pmd mode for guest os)
32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-config
To verify the use of the virtio PMD mode in the guest operating
system, the following patch needs to be applied to QEMU:
https://lore.kernel.org/all/20240408073311.2049-1-yuxue.liu@jaguarmicro.com
Signed-off-by: Yuxue Liu <yuxue.liu@jaguarmicro.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
V4: Update the title and assign values to uninitialized variables
V3: delete unused variables and add validation records
V2: fix when allocating IRQs, scan all queues
drivers/vdpa/virtio_pci/vp_vdpa.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)
diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
index df5f4a3bccb5..74bc8adfc7e8 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -160,7 +160,14 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
struct pci_dev *pdev = mdev->pci_dev;
int i, ret, irq;
int queues = vp_vdpa->queues;
- int vectors = queues + 1;
+ int vectors = 0;
+ int msix_vec = 0;
+
+ for (i = 0; i < queues; i++) {
+ if (vp_vdpa->vring[i].cb.callback)
+ vectors++;
+ }
+ vectors++;
ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
if (ret != vectors) {
@@ -173,9 +180,12 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
vp_vdpa->vectors = vectors;
for (i = 0; i < queues; i++) {
+ if (!vp_vdpa->vring[i].cb.callback)
+ continue;
+
snprintf(vp_vdpa->vring[i].msix_name, VP_VDPA_NAME_SIZE,
"vp-vdpa[%s]-%d\n", pci_name(pdev), i);
- irq = pci_irq_vector(pdev, i);
+ irq = pci_irq_vector(pdev, msix_vec);
ret = devm_request_irq(&pdev->dev, irq,
vp_vdpa_vq_handler,
0, vp_vdpa->vring[i].msix_name,
@@ -185,21 +195,22 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
"vp_vdpa: fail to request irq for vq %d\n", i);
goto err;
}
- vp_modern_queue_vector(mdev, i, i);
+ vp_modern_queue_vector(mdev, i, msix_vec);
vp_vdpa->vring[i].irq = irq;
+ msix_vec++;
}
snprintf(vp_vdpa->msix_name, VP_VDPA_NAME_SIZE, "vp-vdpa[%s]-config\n",
pci_name(pdev));
- irq = pci_irq_vector(pdev, queues);
+ irq = pci_irq_vector(pdev, msix_vec);
ret = devm_request_irq(&pdev->dev, irq, vp_vdpa_config_handler, 0,
vp_vdpa->msix_name, vp_vdpa);
if (ret) {
dev_err(&pdev->dev,
- "vp_vdpa: fail to request irq for vq %d\n", i);
+ "vp_vdpa: fail to request irq for config, ret %d\n", ret);
goto err;
}
- vp_modern_config_vector(mdev, queues);
+ vp_modern_config_vector(mdev, msix_vec);
vp_vdpa->config_irq = irq;
return 0;
--
2.43.0
在 2024/4/9 下午4:58, lyx634449800 写道:
> From: Yuxue Liu <yuxue.liu@jaguarmicro.com>
>
> When there is a ctlq and it doesn't require interrupt
> callbacks,the original method of calculating vectors
> wastes hardware msi or msix resources as well as system
> IRQ resources.
>
> When conducting performance testing using testpmd in the
> guest os, it was found that the performance was lower compared
> to directly using vfio-pci to passthrough the device
>
> In scenarios where the virtio device in the guest os does
> not utilize interrupts, the vdpa driver still configures
> the hardware's msix vector. Therefore, the hardware still
> sends interrupts to the host os. Because of this unnecessary
> action by the hardware, hardware performance decreases, and
> it also affects the performance of the host os.
>
> Before modification:(interrupt mode)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
> 35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
>
> After modification:(interrupt mode)
> 32: 0 0 1 7 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 36 0 3 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-config
>
> Before modification:(virtio pmd mode for guest os)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
> 35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
>
> After modification:(virtio pmd mode for guest os)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-config
>
> To verify the use of the virtio PMD mode in the guest operating
> system, the following patch needs to be applied to QEMU:
> https://lore.kernel.org/all/20240408073311.2049-1-yuxue.liu@jaguarmicro.com
>
> Signed-off-by: Yuxue Liu <yuxue.liu@jaguarmicro.com>
> Acked-by: Jason Wang <jasowang@redhat.com>
> ---
> V4: Update the title and assign values to uninitialized variables
> V3: delete unused variables and add validation records
> V2: fix when allocating IRQs, scan all queues
>
> drivers/vdpa/virtio_pci/vp_vdpa.c | 23 +++++++++++++++++------
> 1 file changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> index df5f4a3bccb5..74bc8adfc7e8 100644
> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> @@ -160,7 +160,14 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> struct pci_dev *pdev = mdev->pci_dev;
> int i, ret, irq;
> int queues = vp_vdpa->queues;
> - int vectors = queues + 1;
> + int vectors = 0;
> + int msix_vec = 0;
> +
> + for (i = 0; i < queues; i++) {
> + if (vp_vdpa->vring[i].cb.callback)
> + vectors++;
> + }
> + vectors++;
>
> ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
> if (ret != vectors) {
> @@ -173,9 +180,12 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> vp_vdpa->vectors = vectors;
>
> for (i = 0; i < queues; i++) {
> + if (!vp_vdpa->vring[i].cb.callback)
> + continue;
> +
> snprintf(vp_vdpa->vring[i].msix_name, VP_VDPA_NAME_SIZE,
> "vp-vdpa[%s]-%d\n", pci_name(pdev), i);
> - irq = pci_irq_vector(pdev, i);
> + irq = pci_irq_vector(pdev, msix_vec);
> ret = devm_request_irq(&pdev->dev, irq,
> vp_vdpa_vq_handler,
> 0, vp_vdpa->vring[i].msix_name,
> @@ -185,21 +195,22 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> "vp_vdpa: fail to request irq for vq %d\n", i);
> goto err;
> }
> - vp_modern_queue_vector(mdev, i, i);
> + vp_modern_queue_vector(mdev, i, msix_vec);
> vp_vdpa->vring[i].irq = irq;
> + msix_vec++;
> }
>
> snprintf(vp_vdpa->msix_name, VP_VDPA_NAME_SIZE, "vp-vdpa[%s]-config\n",
> pci_name(pdev));
> - irq = pci_irq_vector(pdev, queues);
> + irq = pci_irq_vector(pdev, msix_vec);
> ret = devm_request_irq(&pdev->dev, irq, vp_vdpa_config_handler, 0,
> vp_vdpa->msix_name, vp_vdpa);
> if (ret) {
> dev_err(&pdev->dev,
> - "vp_vdpa: fail to request irq for vq %d\n", i);
> + "vp_vdpa: fail to request irq for config, ret %d\n", ret);
> goto err;
> }
> - vp_modern_config_vector(mdev, queues);
> + vp_modern_config_vector(mdev, msix_vec);
> vp_vdpa->config_irq = irq;
>
> return 0;
Reviewed-by: Heng Qi <hengqi@linux.alibaba.com>
From: Yuxue Liu <yuxue.liu@jaguarmicro.com>
When there is a ctlq and it doesn't require interrupt
callbacks,the original method of calculating vectors
wastes hardware msi or msix resources as well as system
IRQ resources.
When conducting performance testing using testpmd in the
guest os, it was found that the performance was lower compared
to directly using vfio-pci to passthrough the device
In scenarios where the virtio device in the guest os does
not utilize interrupts, the vdpa driver still configures
the hardware's msix vector. Therefore, the hardware still
sends interrupts to the host os. Because of this unnecessary
action by the hardware, hardware performance decreases, and
it also affects the performance of the host os.
Before modification:(interrupt mode)
32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
After modification:(interrupt mode)
32: 0 0 1 7 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
33: 36 0 3 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-config
Before modification:(virtio pmd mode for guest os)
32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
After modification:(virtio pmd mode for guest os)
32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-config
To verify the use of the virtio PMD mode in the guest operating
system, the following patch needs to be applied to QEMU:
https://lore.kernel.org/all/20240408073311.2049-1-yuxue.liu@jaguarmicro.com
Signed-off-by: Yuxue Liu <yuxue.liu@jaguarmicro.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Heng Qi <hengqi@linux.alibaba.com>
---
V5: modify the description of the printout when an exception occurs
V4: update the title and assign values to uninitialized variables
V3: delete unused variables and add validation records
V2: fix when allocating IRQs, scan all queues
drivers/vdpa/virtio_pci/vp_vdpa.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
index df5f4a3bccb5..8de0224e9ec2 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -160,7 +160,13 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
struct pci_dev *pdev = mdev->pci_dev;
int i, ret, irq;
int queues = vp_vdpa->queues;
- int vectors = queues + 1;
+ int vectors = 1;
+ int msix_vec = 0;
+
+ for (i = 0; i < queues; i++) {
+ if (vp_vdpa->vring[i].cb.callback)
+ vectors++;
+ }
ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
if (ret != vectors) {
@@ -173,9 +179,12 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
vp_vdpa->vectors = vectors;
for (i = 0; i < queues; i++) {
+ if (!vp_vdpa->vring[i].cb.callback)
+ continue;
+
snprintf(vp_vdpa->vring[i].msix_name, VP_VDPA_NAME_SIZE,
"vp-vdpa[%s]-%d\n", pci_name(pdev), i);
- irq = pci_irq_vector(pdev, i);
+ irq = pci_irq_vector(pdev, msix_vec);
ret = devm_request_irq(&pdev->dev, irq,
vp_vdpa_vq_handler,
0, vp_vdpa->vring[i].msix_name,
@@ -185,21 +194,22 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
"vp_vdpa: fail to request irq for vq %d\n", i);
goto err;
}
- vp_modern_queue_vector(mdev, i, i);
+ vp_modern_queue_vector(mdev, i, msix_vec);
vp_vdpa->vring[i].irq = irq;
+ msix_vec++;
}
snprintf(vp_vdpa->msix_name, VP_VDPA_NAME_SIZE, "vp-vdpa[%s]-config\n",
pci_name(pdev));
- irq = pci_irq_vector(pdev, queues);
+ irq = pci_irq_vector(pdev, msix_vec);
ret = devm_request_irq(&pdev->dev, irq, vp_vdpa_config_handler, 0,
vp_vdpa->msix_name, vp_vdpa);
if (ret) {
dev_err(&pdev->dev,
- "vp_vdpa: fail to request irq for vq %d\n", i);
+ "vp_vdpa: fail to request irq for config: %d\n", ret);
goto err;
}
- vp_modern_config_vector(mdev, queues);
+ vp_modern_config_vector(mdev, msix_vec);
vp_vdpa->config_irq = irq;
return 0;
--
2.43.0On Wed, Apr 10, 2024 at 11:30:20AM +0800, lyx634449800 wrote:
> From: Yuxue Liu <yuxue.liu@jaguarmicro.com>
>
> When there is a ctlq and it doesn't require interrupt
> callbacks,the original method of calculating vectors
> wastes hardware msi or msix resources as well as system
> IRQ resources.
>
> When conducting performance testing using testpmd in the
> guest os, it was found that the performance was lower compared
> to directly using vfio-pci to passthrough the device
>
> In scenarios where the virtio device in the guest os does
> not utilize interrupts, the vdpa driver still configures
> the hardware's msix vector. Therefore, the hardware still
> sends interrupts to the host os.
I just have a question on this part. How come hardware
sends interrupts does not guest driver disable them?
> Because of this unnecessary
> action by the hardware, hardware performance decreases, and
> it also affects the performance of the host os.
>
> Before modification:(interrupt mode)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
> 35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
>
> After modification:(interrupt mode)
> 32: 0 0 1 7 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 36 0 3 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-config
>
> Before modification:(virtio pmd mode for guest os)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
> 35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
>
> After modification:(virtio pmd mode for guest os)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-config
>
> To verify the use of the virtio PMD mode in the guest operating
> system, the following patch needs to be applied to QEMU:
> https://lore.kernel.org/all/20240408073311.2049-1-yuxue.liu@jaguarmicro.com
>
> Signed-off-by: Yuxue Liu <yuxue.liu@jaguarmicro.com>
> Acked-by: Jason Wang <jasowang@redhat.com>
> Reviewed-by: Heng Qi <hengqi@linux.alibaba.com>
> ---
> V5: modify the description of the printout when an exception occurs
> V4: update the title and assign values to uninitialized variables
> V3: delete unused variables and add validation records
> V2: fix when allocating IRQs, scan all queues
>
> drivers/vdpa/virtio_pci/vp_vdpa.c | 22 ++++++++++++++++------
> 1 file changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> index df5f4a3bccb5..8de0224e9ec2 100644
> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> @@ -160,7 +160,13 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> struct pci_dev *pdev = mdev->pci_dev;
> int i, ret, irq;
> int queues = vp_vdpa->queues;
> - int vectors = queues + 1;
> + int vectors = 1;
> + int msix_vec = 0;
> +
> + for (i = 0; i < queues; i++) {
> + if (vp_vdpa->vring[i].cb.callback)
> + vectors++;
> + }
>
> ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
> if (ret != vectors) {
> @@ -173,9 +179,12 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> vp_vdpa->vectors = vectors;
>
> for (i = 0; i < queues; i++) {
> + if (!vp_vdpa->vring[i].cb.callback)
> + continue;
> +
> snprintf(vp_vdpa->vring[i].msix_name, VP_VDPA_NAME_SIZE,
> "vp-vdpa[%s]-%d\n", pci_name(pdev), i);
> - irq = pci_irq_vector(pdev, i);
> + irq = pci_irq_vector(pdev, msix_vec);
> ret = devm_request_irq(&pdev->dev, irq,
> vp_vdpa_vq_handler,
> 0, vp_vdpa->vring[i].msix_name,
> @@ -185,21 +194,22 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> "vp_vdpa: fail to request irq for vq %d\n", i);
> goto err;
> }
> - vp_modern_queue_vector(mdev, i, i);
> + vp_modern_queue_vector(mdev, i, msix_vec);
> vp_vdpa->vring[i].irq = irq;
> + msix_vec++;
> }
>
> snprintf(vp_vdpa->msix_name, VP_VDPA_NAME_SIZE, "vp-vdpa[%s]-config\n",
> pci_name(pdev));
> - irq = pci_irq_vector(pdev, queues);
> + irq = pci_irq_vector(pdev, msix_vec);
> ret = devm_request_irq(&pdev->dev, irq, vp_vdpa_config_handler, 0,
> vp_vdpa->msix_name, vp_vdpa);
> if (ret) {
> dev_err(&pdev->dev,
> - "vp_vdpa: fail to request irq for vq %d\n", i);
> + "vp_vdpa: fail to request irq for config: %d\n", ret);
> goto err;
> }
> - vp_modern_config_vector(mdev, queues);
> + vp_modern_config_vector(mdev, msix_vec);
> vp_vdpa->config_irq = irq;
>
> return 0;
> --
> 2.43.0
Good and clear subject, I like it.
On Tue, Apr 09, 2024 at 04:58:18PM +0800, lyx634449800 wrote:
> From: Yuxue Liu <yuxue.liu@jaguarmicro.com>
>
> When there is a ctlq and it doesn't require interrupt
> callbacks,the original method of calculating vectors
> wastes hardware msi or msix resources as well as system
> IRQ resources.
>
> When conducting performance testing using testpmd in the
> guest os, it was found that the performance was lower compared
> to directly using vfio-pci to passthrough the device
>
> In scenarios where the virtio device in the guest os does
> not utilize interrupts, the vdpa driver still configures
> the hardware's msix vector. Therefore, the hardware still
> sends interrupts to the host os. Because of this unnecessary
> action by the hardware, hardware performance decreases, and
> it also affects the performance of the host os.
>
> Before modification:(interrupt mode)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
> 35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
>
> After modification:(interrupt mode)
> 32: 0 0 1 7 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 36 0 3 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-config
>
> Before modification:(virtio pmd mode for guest os)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
> 35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
>
> After modification:(virtio pmd mode for guest os)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-config
>
> To verify the use of the virtio PMD mode in the guest operating
> system, the following patch needs to be applied to QEMU:
> https://lore.kernel.org/all/20240408073311.2049-1-yuxue.liu@jaguarmicro.com
>
> Signed-off-by: Yuxue Liu <yuxue.liu@jaguarmicro.com>
> Acked-by: Jason Wang <jasowang@redhat.com>
Much better, thanks!
A couple of small tweaks to polish it up and it'll be ready.
> ---
> V4: Update the title and assign values to uninitialized variables
> V3: delete unused variables and add validation records
> V2: fix when allocating IRQs, scan all queues
>
> drivers/vdpa/virtio_pci/vp_vdpa.c | 23 +++++++++++++++++------
> 1 file changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> index df5f4a3bccb5..74bc8adfc7e8 100644
> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> @@ -160,7 +160,14 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> struct pci_dev *pdev = mdev->pci_dev;
> int i, ret, irq;
> int queues = vp_vdpa->queues;
> - int vectors = queues + 1;
> + int vectors = 0;
> + int msix_vec = 0;
> +
> + for (i = 0; i < queues; i++) {
> + if (vp_vdpa->vring[i].cb.callback)
> + vectors++;
> + }
> + vectors++;
Actually even easier: int vectors = 1; and then we do not need
this last line.
Sorry I only noticed now.
>
> ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
> if (ret != vectors) {
> @@ -173,9 +180,12 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> vp_vdpa->vectors = vectors;
>
> for (i = 0; i < queues; i++) {
> + if (!vp_vdpa->vring[i].cb.callback)
> + continue;
> +
> snprintf(vp_vdpa->vring[i].msix_name, VP_VDPA_NAME_SIZE,
> "vp-vdpa[%s]-%d\n", pci_name(pdev), i);
> - irq = pci_irq_vector(pdev, i);
> + irq = pci_irq_vector(pdev, msix_vec);
> ret = devm_request_irq(&pdev->dev, irq,
> vp_vdpa_vq_handler,
> 0, vp_vdpa->vring[i].msix_name,
> @@ -185,21 +195,22 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> "vp_vdpa: fail to request irq for vq %d\n", i);
> goto err;
> }
> - vp_modern_queue_vector(mdev, i, i);
> + vp_modern_queue_vector(mdev, i, msix_vec);
> vp_vdpa->vring[i].irq = irq;
> + msix_vec++;
> }
>
> snprintf(vp_vdpa->msix_name, VP_VDPA_NAME_SIZE, "vp-vdpa[%s]-config\n",
> pci_name(pdev));
> - irq = pci_irq_vector(pdev, queues);
> + irq = pci_irq_vector(pdev, msix_vec);
> ret = devm_request_irq(&pdev->dev, irq, vp_vdpa_config_handler, 0,
> vp_vdpa->msix_name, vp_vdpa);
> if (ret) {
> dev_err(&pdev->dev,
> - "vp_vdpa: fail to request irq for vq %d\n", i);
> + "vp_vdpa: fail to request irq for config, ret %d\n", ret);
As long as we are here let's fix the grammar, and there's no need to
say "ret":
"vp_vdpa: failed to request irq for config: %d\n", ret);
> goto err;
> }
> - vp_modern_config_vector(mdev, queues);
> + vp_modern_config_vector(mdev, msix_vec);
> vp_vdpa->config_irq = irq;
>
> return 0;
> --
> 2.43.0
On Tue, Apr 9, 2024 at 9:49 AM lyx634449800 <yuxue.liu@jaguarmicro.com> wrote:
>
> When there is a ctlq and it doesn't require interrupt
> callbacks,the original method of calculating vectors
> wastes hardware msi or msix resources as well as system
> IRQ resources.
>
> When conducting performance testing using testpmd in the
> guest os, it was found that the performance was lower compared
> to directly using vfio-pci to passthrough the device
>
> In scenarios where the virtio device in the guest os does
> not utilize interrupts, the vdpa driver still configures
> the hardware's msix vector. Therefore, the hardware still
> sends interrupts to the host os. Because of this unnecessary
> action by the hardware, hardware performance decreases, and
> it also affects the performance of the host os.
>
> Before modification:(interrupt mode)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
> 35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
>
> After modification:(interrupt mode)
> 32: 0 0 1 7 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 36 0 3 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-config
>
> Before modification:(virtio pmd mode for guest os)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-0
> 33: 0 0 0 0 PCI-MSI 32769-edge vp-vdpa[0000:00:02.0]-1
> 34: 0 0 0 0 PCI-MSI 32770-edge vp-vdpa[0000:00:02.0]-2
> 35: 0 0 0 0 PCI-MSI 32771-edge vp-vdpa[0000:00:02.0]-config
>
> After modification:(virtio pmd mode for guest os)
> 32: 0 0 0 0 PCI-MSI 32768-edge vp-vdpa[0000:00:02.0]-config
>
> To verify the use of the virtio PMD mode in the guest operating
> system, the following patch needs to be applied to QEMU:
> https://lore.kernel.org/all/20240408073311.2049-1-yuxue.liu@jaguarmicro.com
>
> Signed-off-by: lyx634449800 <yuxue.liu@jaguarmicro.com>
> ---
>
> V3: delete unused variables and add validation records
> V2: fix when allocating IRQs, scan all queues
>
> drivers/vdpa/virtio_pci/vp_vdpa.c | 35 +++++++++++++++++++------------
> 1 file changed, 22 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> index df5f4a3bccb5..cd3aeb3b8f21 100644
> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> @@ -160,22 +160,31 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> struct pci_dev *pdev = mdev->pci_dev;
> int i, ret, irq;
> int queues = vp_vdpa->queues;
> - int vectors = queues + 1;
> + int msix_vec, allocated_vectors = 0;
>
> - ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
> - if (ret != vectors) {
> + for (i = 0; i < queues; i++) {
> + if (vp_vdpa->vring[i].cb.callback)
> + allocated_vectors++;
> + }
> + allocated_vectors = allocated_vectors + 1;
> +
> + ret = pci_alloc_irq_vectors(pdev, allocated_vectors, allocated_vectors,
> + PCI_IRQ_MSIX);
> + if (ret != allocated_vectors) {
> dev_err(&pdev->dev,
> "vp_vdpa: fail to allocate irq vectors want %d but %d\n",
> - vectors, ret);
> + allocated_vectors, ret);
> return ret;
> }
> -
> - vp_vdpa->vectors = vectors;
> + vp_vdpa->vectors = allocated_vectors;
>
> for (i = 0; i < queues; i++) {
> + if (!vp_vdpa->vring[i].cb.callback)
> + continue;
> +
> snprintf(vp_vdpa->vring[i].msix_name, VP_VDPA_NAME_SIZE,
> "vp-vdpa[%s]-%d\n", pci_name(pdev), i);
> - irq = pci_irq_vector(pdev, i);
> + irq = pci_irq_vector(pdev, msix_vec);
> ret = devm_request_irq(&pdev->dev, irq,
> vp_vdpa_vq_handler,
> 0, vp_vdpa->vring[i].msix_name,
> @@ -185,23 +194,23 @@ static int vp_vdpa_request_irq(struct vp_vdpa *vp_vdpa)
> "vp_vdpa: fail to request irq for vq %d\n", i);
> goto err;
> }
> - vp_modern_queue_vector(mdev, i, i);
> + vp_modern_queue_vector(mdev, i, msix_vec);
> vp_vdpa->vring[i].irq = irq;
> + msix_vec++;
> }
>
> snprintf(vp_vdpa->msix_name, VP_VDPA_NAME_SIZE, "vp-vdpa[%s]-config\n",
> - pci_name(pdev));
> - irq = pci_irq_vector(pdev, queues);
> + pci_name(pdev));
> + irq = pci_irq_vector(pdev, msix_vec);
> ret = devm_request_irq(&pdev->dev, irq, vp_vdpa_config_handler, 0,
> vp_vdpa->msix_name, vp_vdpa);
> if (ret) {
> dev_err(&pdev->dev,
> - "vp_vdpa: fail to request irq for vq %d\n", i);
> + "vp_vdpa: fail to request irq for config\n");
> goto err;
> }
> - vp_modern_config_vector(mdev, queues);
> + vp_modern_config_vector(mdev, msix_vec);
> vp_vdpa->config_irq = irq;
> -
Unnecessary changes.
Others look good.
Acked-by: Jason Wang <jasowang@redhat.com>
Thanks
> return 0;
> err:
> vp_vdpa_free_irq(vp_vdpa);
> --
> 2.43.0
>
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