e7ef688562
This patch reorders the code to delay virtio header write to improve cache access efficiency for cases where the mrg_rxbuf feature is turned on. CPU pipeline stall cycles can be significantly reduced. Virtio header write and mbuf data copy are all remote store operations which takes a long time to finish. It's a good idea to put them together to remove bubbles in between, to let as many remote store instructions as possible go into store buffer at the same time to hide latency, and to let the H/W prefetcher goes to work as early as possible. On a Haswell machine, about 100 cycles can be saved per packet by this patch alone. Taking 64B packets traffic for example, this means about 60% efficiency improvement for the enqueue operation. Signed-off-by: Zhihong Wang <zhihong.wang@intel.com> Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com> Reviewed-by: Jianbo Liu <jianbo.liu@linaro.org> Tested-by: Maxime Coquelin <maxime.coquelin@redhat.com>
DPDK is a set of libraries and drivers for fast packet processing. It supports many processor architectures and both FreeBSD and Linux. The DPDK uses the Open Source BSD license for the core libraries and drivers. The kernel components are GPLv2 licensed. Please check the doc directory for release notes, API documentation, and sample application information. For questions and usage discussions, subscribe to: users@dpdk.org Report bugs and issues to the development mailing list: dev@dpdk.org