Re: Re: Re: [PATCH v2 0/2] virtio: abstract virtqueue related methods

From: zhenwei pi
Date: Wed May 17 2023 - 01:01:01 EST


On 5/17/23 11:57, Michael S. Tsirkin wrote:
On Wed, May 17, 2023 at 11:51:03AM +0800, zhenwei pi wrote:


On 5/17/23 11:46, Michael S. Tsirkin wrote:
On Wed, May 17, 2023 at 10:54:22AM +0800, zhenwei pi wrote:
v1 -> v2:
- Suggested by MST, use fast path for vring based performance
sensitive API.
- Reduce changes in tools/virtio.

Add test result(no obvious change):
Before:
time ./vringh_test --parallel
Using CPUS 0 and 191
Guest: notified 10036893, pinged 68278
Host: notified 68278, pinged 3093532

real 0m14.463s
user 0m6.437s
sys 0m8.010s

After:
time ./vringh_test --parallel
Using CPUS 0 and 191
Guest: notified 10036709, pinged 68347
Host: notified 68347, pinged 3085292

real 0m14.196s
user 0m6.289s
sys 0m7.885s

v1:
Hi,

3 weeks ago, I posted a proposal 'Virtio Over Fabrics':
https://lists.oasis-open.org/archives/virtio-comment/202304/msg00442.html

Jason and Stefan pointed out that a non-vring based virtqueue has a
chance to overwrite virtqueue instead of using vring virtqueue.

Then I try to abstract virtqueue related methods in this series, the
details changes see the comment of patch 'virtio: abstract virtqueue related methods'.

Something is still remained:
- __virtqueue_break/__virtqueue_unbreak is supposed to use by internal
virtio core, I'd like to rename them to vring_virtqueue_break
/vring_virtqueue_unbreak. Is this reasonable?

Why? These just set a flag?


Rename '__virtqueue_break' to 'vring_virtqueue_break', to make symbols
exported from virtio_ring.ko have unified prefix 'vring_virtqueue_xxx'.

I just do not see why you need these callbacks at all.


I use these callbacks for break/unbreak device like:
static inline void virtio_break_device(struct virtio_device *dev)
{
struct virtqueue *vq;

spin_lock(&dev->vqs_list_lock);
list_for_each_entry(vq, &dev->vqs, list) {
vq->__break(vq);
}
spin_unlock(&dev->vqs_list_lock);
}

- virtqueue_get_desc_addr/virtqueue_get_avail_addr/virtqueue_get_used_addr
/virtqueue_get_vring is vring specific, I'd like to rename them like
vring_virtqueue_get_desc_addr. Is this reasonable?
- there are still some functions in virtio_ring.c with prefix *virtqueue*,
for example 'virtqueue_add_split', just keep it or rename it to
'vring_virtqueue_add_split'?
zhenwei pi (2):
virtio: abstract virtqueue related methods
tools/virtio: implement virtqueue in test

drivers/virtio/virtio_ring.c | 285 +++++-----------------
include/linux/virtio.h | 441 +++++++++++++++++++++++++++++++----
include/linux/virtio_ring.h | 26 +++
tools/virtio/linux/virtio.h | 355 +++++++++++++++++++++++++---
4 files changed, 807 insertions(+), 300 deletions(-)

--
2.20.1


--
zhenwei pi


--
zhenwei pi