If the VIRTIO_RING_F_INDIRECT_DESC negotiation succeeds, and the number
of sgs used for sending packets is greater than 1. We must constantly
call __kmalloc/kfree to allocate/release desc.
In the case of extremely fast package delivery, the overhead cannot be
ignored:
27.46% [kernel] [k] virtqueue_add
16.66% [kernel] [k] detach_buf_split
16.51% [kernel] [k] virtnet_xsk_xmit
14.04% [kernel] [k] virtqueue_add_outbuf
5.18% [kernel] [k] __kmalloc
4.08% [kernel] [k] kfree
2.80% [kernel] [k] virtqueue_get_buf_ctx
2.22% [kernel] [k] xsk_tx_peek_desc
2.08% [kernel] [k] memset_erms
0.83% [kernel] [k] virtqueue_kick_prepare
0.76% [kernel] [k] virtnet_xsk_run
0.62% [kernel] [k] __free_old_xmit_ptr
0.60% [kernel] [k] vring_map_one_sg
0.53% [kernel] [k] native_apic_mem_write
0.46% [kernel] [k] sg_next
0.43% [kernel] [k] sg_init_table
0.41% [kernel] [k] kmalloc_slab
This patch adds a cache function to virtio to cache these allocated indirect
desc instead of constantly allocating and releasing desc.
v4:
1. Only allow desc cache when VIRTIO_RING_F_INDIRECT_DESC negotiation is
successful
2. The desc cache threshold can be set for each virtqueue
v3:
pre-allocate per buffer indirect descriptors array
v2:
use struct list_head to cache the desc
Xuan Zhuo (3):
virtio: cache indirect desc for split
virtio: cache indirect desc for packed
virtio-net: enable virtio desc cache
drivers/net/virtio_net.c | 12 ++-
drivers/virtio/virtio_ring.c | 152 +++++++++++++++++++++++++++++++----
include/linux/virtio.h | 17 ++++
3 files changed, 163 insertions(+), 18 deletions(-)
--
2.31.0
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