On Wed, Feb 28, 2024 at 05:30:07PM +0800, Yunsheng Lin wrote: > Currently there are three implementations for page frag: > > 1. mm/page_alloc.c: net stack seems to be using it in the > rx part with 'struct page_frag_cache' and the main API > being page_frag_alloc_align(). > 2. net/core/sock.c: net stack seems to be using it in the > tx part with 'struct page_frag' and the main API being > skb_page_frag_refill(). > 3. drivers/vhost/net.c: vhost seems to be using it to build > xdp frame, and it's implementation seems to be a mix of > the above two. > > This patchset tries to unfiy the page frag implementation a > little bit by unifying gfp bit for order 3 page allocation > and replacing page frag implementation in vhost.c with the > one in page_alloc.c. > > After this patchset, we are not only able to unify the page > frag implementation a little, but also able to have about > 0.5% performance boost testing by using the vhost_net_test > introduced in the last patch. > > Before this patchset: > Performance counter stats for './vhost_net_test' (10 runs): > > 305325.78 msec task-clock # 1.738 CPUs utilized ( +- 0.12% ) > 1048668 context-switches # 3.435 K/sec ( +- 0.00% ) > 11 cpu-migrations # 0.036 /sec ( +- 17.64% ) > 33 page-faults # 0.108 /sec ( +- 0.49% ) > 244651819491 cycles # 0.801 GHz ( +- 0.43% ) (64) > 64714638024 stalled-cycles-frontend # 26.45% frontend cycles idle ( +- 2.19% ) (67) > 30774313491 stalled-cycles-backend # 12.58% backend cycles idle ( +- 7.68% ) (70) > 201749748680 instructions # 0.82 insn per cycle > # 0.32 stalled cycles per insn ( +- 0.41% ) (66.76%) > 65494787909 branches # 214.508 M/sec ( +- 0.35% ) (64) > 4284111313 branch-misses # 6.54% of all branches ( +- 0.45% ) (66) > > 175.699 +- 0.189 seconds time elapsed ( +- 0.11% ) > > > After this patchset: > Performance counter stats for './vhost_net_test' (10 runs): > > 303974.38 msec task-clock # 1.739 CPUs utilized ( +- 0.14% ) > 1048807 context-switches # 3.450 K/sec ( +- 0.00% ) > 14 cpu-migrations # 0.046 /sec ( +- 12.86% ) > 33 page-faults # 0.109 /sec ( +- 0.46% ) > 251289376347 cycles # 0.827 GHz ( +- 0.32% ) (60) > 67885175415 stalled-cycles-frontend # 27.01% frontend cycles idle ( +- 0.48% ) (63) > 27809282600 stalled-cycles-backend # 11.07% backend cycles idle ( +- 0.36% ) (71) > 195543234672 instructions # 0.78 insn per cycle > # 0.35 stalled cycles per insn ( +- 0.29% ) (69.04%) > 62423183552 branches # 205.357 M/sec ( +- 0.48% ) (67) > 4135666632 branch-misses # 6.63% of all branches ( +- 0.63% ) (67) > > 174.764 +- 0.214 seconds time elapsed ( +- 0.12% ) The perf diff is in the noise, but the cleanup is nice. Thanks! Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > Changelog: > V6: Add timeout for poll() and simplify some logic as suggested > by Jason. > > V5: Address the comment from jason in vhost_net_test.c and the > comment about leaving out the gfp change for page frag in > sock.c as suggested by Paolo. > > V4: Resend based on latest net-next branch. > > V3: > 1. Add __page_frag_alloc_align() which is passed with the align mask > the original function expected as suggested by Alexander. > 2. Drop patch 3 in v2 suggested by Alexander. > 3. Reorder patch 4 & 5 in v2 suggested by Alexander. > > Note that placing this gfp flags handing for order 3 page in an inline > function is not considered, as we may be able to unify the page_frag > and page_frag_cache handling. > > V2: Change 'xor'd' to 'masked off', add vhost tx testing for > vhost_net_test. > > V1: Fix some typo, drop RFC tag and rebase on latest net-next. > > Yunsheng Lin (5): > mm/page_alloc: modify page_frag_alloc_align() to accept align as an > argument > page_frag: unify gfp bits for order 3 page allocation > net: introduce page_frag_cache_drain() > vhost/net: remove vhost_net_page_frag_refill() > tools: virtio: introduce vhost_net_test > > drivers/net/ethernet/google/gve/gve_main.c | 11 +- > drivers/net/ethernet/mediatek/mtk_wed_wo.c | 17 +- > drivers/nvme/host/tcp.c | 7 +- > drivers/nvme/target/tcp.c | 4 +- > drivers/vhost/net.c | 91 ++-- > include/linux/gfp.h | 16 +- > mm/page_alloc.c | 22 +- > net/core/skbuff.c | 9 +- > tools/virtio/.gitignore | 1 + > tools/virtio/Makefile | 8 +- > tools/virtio/linux/virtio_config.h | 4 + > tools/virtio/vhost_net_test.c | 532 +++++++++++++++++++++ > 12 files changed, 609 insertions(+), 113 deletions(-) > create mode 100644 tools/virtio/vhost_net_test.c > > -- > 2.33.0 >
