0a0be13b8f
This patch implements XDP batching for vhost_net. The idea is first to try to do userspace copy and build XDP buff directly in vhost. Instead of submitting the packet immediately, vhost_net will batch them in an array and submit every 64 (VHOST_NET_BATCH) packets to the under layer sockets through msg_control of sendmsg(). When XDP is enabled on the TUN/TAP, TUN/TAP can process XDP inside a loop without caring GUP thus it can do batch map flushing. When XDP is not enabled or not supported, the underlayer socket need to build skb and pass it to network core. The batched packet submission allows us to do batching like netif_receive_skb_list() in the future. This saves lots of indirect calls for better cache utilization. For the case that we can't so batching e.g when sndbuf is limited or packet size is too large, we will go for usual one packet per sendmsg() way. Doing testpmd on various setups gives us: Test /+pps% XDP_DROP on TAP /+44.8% XDP_REDIRECT on TAP /+29% macvtap (skb) /+26% Netperf tests shows obvious improvements for small packet transmission: size/session/+thu%/+normalize% 64/ 1/ +2%/ 0% 64/ 2/ +3%/ +1% 64/ 4/ +7%/ +5% 64/ 8/ +8%/ +6% 256/ 1/ +3%/ 0% 256/ 2/ +10%/ +7% 256/ 4/ +26%/ +22% 256/ 8/ +27%/ +23% 512/ 1/ +3%/ +2% 512/ 2/ +19%/ +14% 512/ 4/ +43%/ +40% 512/ 8/ +45%/ +41% 1024/ 1/ +4%/ 0% 1024/ 2/ +27%/ +21% 1024/ 4/ +38%/ +73% 1024/ 8/ +15%/ +24% 2048/ 1/ +10%/ +7% 2048/ 2/ +16%/ +12% 2048/ 4/ 0%/ +2% 2048/ 8/ 0%/ +2% 4096/ 1/ +36%/ +60% 4096/ 2/ -11%/ -26% 4096/ 4/ 0%/ +14% 4096/ 8/ 0%/ +4% 16384/ 1/ -1%/ +5% 16384/ 2/ 0%/ +2% 16384/ 4/ 0%/ -3% 16384/ 8/ 0%/ +4% 65535/ 1/ 0%/ +10% 65535/ 2/ 0%/ +8% 65535/ 4/ 0%/ +1% 65535/ 8/ 0%/ +3% Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.