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CQE compression feature improves performance by reducing PCI bandwidth bottleneck on CQEs write. Enhanced CQE compression introduced in ConnectX-6 and it aims to reduce CPU utilization of SW side packets decompression by eliminating the need to rewrite ownership bit, which is likely to cost a cache-miss, is replaced by validity byte handled solely by HW. Another advantage of the enhanced feature is that session packets are available to SW as soon as a single CQE slot is filled, instead of waiting for session to close, this improves packet latency from NIC to host. Performance: Following are tested scenarios and reults comparing basic and enahnced CQE compression. setup: IXIA 100GbE connected directly to port 0 and port 1 of ConnectX-6 Dx 100GbE dual port. Case #1 RX only, single flow goes to single queue: IRQ rate reduced by ~ 30%, CPU utilization improved by 2%. Case #2 IP forwarding from port 1 to port 0 single flow goes to single queue: Avg latency improved from 60us to 21us, frame loss improved from 0.5% to 0.0%. Case #3 IP forwarding from port 1 to port 0 Max Throughput IXIA sends 100%, 8192 UDP flows, goes to 24 queues: Enhanced is equal or slightly better than basic. Testing the basic compression feature with this patch shows there is no perfrormance degradation of the basic compression feature. Signed-off-by: Ofer Levi <oferle@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Signed-off-by: Saeed Mahameed <saeedm@nvidia.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.