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As we know that AVB is enabled by default, and the ENET IP design is queue 0 for best effort, queue 1&2 for AVB Class A&B. Bandwidth of each queue 1&2 set in driver is 50%, TX bandwidth fluctuated when selecting tx queues randomly with FEC_QUIRK_HAS_AVB quirk available. This patch adds ndo_select_queue callback to select queues for transmitting to fix this issue. It will always return queue 0 if this is not a vlan packet, and return queue 1 or 2 based on priority of vlan packet. You may complain that in fact we only use single queue for trasmitting if we are not targeted to VLAN. Yes, but seems we have no choice, since AVB is enabled when the driver probed, we can't switch this feature dynamicly. After compare multiple queues to single queue, TX throughput almost no improvement. One way we can implemet is to configure the driver to multiple queues with Round-robin scheme by default. Then add ndo_setup_tc callback to enable/disable AVB feature for users. Unfortunately, ENET AVB IP seems not follow the standard 802.1Qav spec. We only can program DMAnCFG[IDLE_SLOPE] field to calculate bandwidth fraction. And idle slope is restricted to certain valus (a total of 19). It's far away from CBS QDisc implemented in Linux TC framework. If you strongly suggest to do this, I think we only can support limited numbers of bandwidth and reject others, but it's really urgly and wried. With this patch, VLAN tagged packets route to queue 0/1/2 based on vlan priority; VLAN untagged packets route to queue 0. Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de> Reported-by: Frieder Schrempf <frieder.schrempf@kontron.de> Signed-off-by: Fugang Duan <fugang.duan@nxp.com> Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| kernel | ||
| lib | ||
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| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
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| COPYING | ||
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| Kbuild | ||
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| 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.
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.