1919b39fc6
The apc->eth_stats.rx_cqes is one per NIC (vport), and it's on the frequent and parallel code path of all queues. So, r/w into this single shared variable by many threads on different CPUs creates a lot caching and memory overhead, hence perf regression. And, it's not accurate due to the high volume concurrent r/w. For example, a workload is iperf with 128 threads, and with RPS enabled. We saw perf regression of 25% with the previous patch adding the counters. And this patch eliminates the regression. Since the error path of mana_poll_rx_cq() already has warnings, so keeping the counter and convert it to a per-queue variable is not necessary. So, just remove this counter from this high frequency code path. Also, remove the tx_cqes counter for the same reason. We have warnings & other counters for errors on that path, and don't need to count every normal cqe processing. Cc: stable@vger.kernel.org Fixes: bd7fc6e1957c ("net: mana: Add new MANA VF performance counters for easier troubleshooting") Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: Horatiu Vultur <horatiu.vultur@microchip.com> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Link: https://lore.kernel.org/r/1685115537-31675-1-git-send-email-haiyangz@microsoft.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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.
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.