[Intel-wired-lan] [PATCH v2 0/5] Introducing ixgbe AF_XDP ZC support
Björn Töpel
bjorn.topel at intel.com
Tue Oct 2 18:39:25 UTC 2018
On 2018-10-02 20:23, William Tu wrote:
> On Tue, Oct 2, 2018 at 1:01 AM Björn Töpel <bjorn.topel at gmail.com> wrote:
>>
>> From: Björn Töpel <bjorn.topel at intel.com>
>>
>> Jeff: Please remove the v1 patches from your dev-queue!
>>
>> This patch set introduces zero-copy AF_XDP support for Intel's ixgbe
>> driver.
>>
>> The ixgbe zero-copy code is located in its own file ixgbe_xsk.[ch],
>> analogous to the i40e ZC support. Again, as in i40e, code paths have
>> been copied from the XDP path to the zero-copy path. Going forward we
>> will try to generalize more code between the AF_XDP ZC drivers, and
>> also reduce the heavy C&P.
>>
>> We have run some benchmarks on a dual socket system with two Broadwell
>> E5 2660 @ 2.0 GHz with hyperthreading turned off. Each socket has 14
>> cores which gives a total of 28, but only two cores are used in these
>> experiments. One for TR/RX and one for the user space application. The
>> memory is DDR4 @ 2133 MT/s (1067 MHz) and the size of each DIMM is
>> 8192MB and with 8 of those DIMMs in the system we have 64 GB of total
>> memory. The compiler used is GCC 7.3.0. The NIC is Intel
>> 82599ES/X520-2 10Gbit/s using the ixgbe driver.
>>
>> Below are the results in Mpps of the 82599ES/X520-2 NIC benchmark runs
>> for 64B and 1500B packets, generated by a commercial packet generator
>> HW blasting packets at full 10Gbit/s line rate. The results are with
>> retpoline and all other spectre and meltdown fixes.
>>
>> AF_XDP performance 64B packets:
>> Benchmark XDP_DRV with zerocopy
>> rxdrop 14.7
>> txpush 14.6
>> l2fwd 11.1
>>
>> AF_XDP performance 1500B packets:
>> Benchmark XDP_DRV with zerocopy
>> rxdrop 0.8
>> l2fwd 0.8
>>
>> XDP performance on our system as a base line.
>>
>> 64B packets:
>> XDP stats CPU Mpps issue-pps
>> XDP-RX CPU 16 14.7 0
>>
>> 1500B packets:
>> XDP stats CPU Mpps issue-pps
>> XDP-RX CPU 16 0.8 0
>>
>> The structure of the patch set is as follows:
>>
>> Patch 1: Introduce Rx/Tx ring enable/disable functionality
>> Patch 2: Preparatory patche to ixgbe driver code for RX
>> Patch 3: ixgbe zero-copy support for RX
>> Patch 4: Preparatory patch to ixgbe driver code for TX
>> Patch 5: ixgbe zero-copy support for TX
>>
>> Changes since v1:
>>
>> * Removed redundant AF_XDP precondition checks, pointed out by
>> Jakub. Now, the preconditions are only checked at XDP enable time.
>> * Fixed a crash in the egress path, due to incorrect usage of
>> ixgbe_ring queue_index member. In v2 a ring_idx back reference is
>> introduced, and used in favor of queue_index. William reported the
>> crash, and helped me smoke out the issue. Kudos!
>
> Thanks! I tested this series and no more crash.
Thank you for spending time on this!
> The number is pretty good (*without* spectre and meltdown fixes)
> model name : Intel(R) Xeon(R) CPU E5-2440 v2 @ 1.90GHz, total 16 cores/
>
> AF_XDP performance 64B packets:
> Benchmark XDP_DRV with zerocopy
> rxdrop 20
> txpush 18
> l2fwd 20
>
What is 20 here? Given that 14.8Mpps is maximum for 64B at 10Gbit/s for
one queue, is this multiple queues? Is this xdpsock or OvS with AF_XDP?
Cheers,
Björn
> Regards,
> William
>
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