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65c482bc22
NAPI Threaded mode (along with the previously enabled SW IRQ Coalescing)
is required to improve network stack performance for single core SoCs
using the GbEth IP (currently the RZ/G2L SoC family and the RZ/G3S SoC).
This patch gives the following improvements during testing with iperf3.
* RZ/G2UL:
* TCP TX: +32% bandwidth (638Mbps -> 841Mbps)
* TXP RX: +8.8% bandwidth (667Mbps -> 726Mbps)
* UDP RX: +104% bandwidth (53Mbps -> 108Mbps)
* RZ/G3S:
* TCP TX: 29% bandwidth (529Mbps -> 681Mbps)
* UDP RX: +1290% bandwidth (6.46Mbps -> 90Mbps)
* RZ/Five:
* UDP RX: Test no longer crashes (0 -> 20 Mbps)
This patch gives the following reductions in performance in the same
testing:
* RZ/G2UL:
* UDP TX: -7.5% bandwidth (594Mbps -> 549Mbps)
* RZ/G3S:
* UDP TX: -5% bandwidth (625Mbps -> 594Mbps)
These losses are considered acceptable given the benefits shown above.
If UDP TX bandwidth must be maximised for a particular use case, NAPI
threaded mode can be disabled at runtime via sysfs writes.
The improvement of UDP RX bandwidth for the single core SoCs (RZ/G2UL &
RZ/G3S) is particularly critical.
Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
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 reStructuredText 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.