Re: [PATCH] app/testpmd: improve sse based macswap

["Varghese, Vipin" <vipin.varghese@amd.com>]

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Hi Bruce,

Thanks for highlighting the variance. We found this was an internal test 
bed configuration issue. We are sharing the next version of the same 
patch with updated numbers.


On 7/23/2024 10:42 PM, Bruce Richardson wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
>
>
> On Tue, Jul 23, 2024 at 05:45:57PM +0100, Ferruh Yigit wrote:
>> On 7/16/2024 7:37 AM, Vipin Varghese wrote:
>>> Goal of the patch is to improve SSE macswap on x86_64 by reducing
>>> the stalls in backend engine. Original implementation of the SSE
>>> macswap makes loop call to multiple load, shuffle & store. Using
>>> SIMD ISA interleaving we can reduce the stalls for
>>>   - load SSE token exhaustion
>>>   - Shuffle and Load dependency
>>>
>>> Also other changes which improves packet per second are
>>>   - Filling access to MBUF for offload flags which is separate cacheline,
>>>   - using register keyword
>>>
>>> Build test using meson script:
>>> ``````````````````````````````
>>>
>>> build-gcc-static
>>> buildtools
>>> build-gcc-shared
>>> build-mini
>>> build-clang-static
>>> build-clang-shared
>>> build-x86-generic
>>>
>>> Test Results:
>>> `````````````
>>>
>>> Platform-1: AMD EPYC SIENA 8594P @2.3GHz, no boost
>>>
>>> ------------------------------------------------
>>> TEST IO 64B: baseline <NIC : MPPs>
>>>   - mellanox CX-7 2*200Gbps : 42.0
>>>   - intel E810 1*100Gbps : 82.0
>>>   - intel E810 2*200Gbps (2CQ-DA2): 82.45
>>> ------------------------------------------------
>>> TEST MACSWAP 64B: <NIC : Before : After>
>>>   - mellanox CX-7 2*200Gbps : 31.533 : 31.90
>>>   - intel E810 1*100Gbps : 50.380 : 47.0
>>>   - intel E810 2*200Gbps (2CQ-DA2): 48.840 : 49.827
>>> ------------------------------------------------
>>> TEST MACSWAP 128B: <NIC : Before: After>
>>>   - mellanox CX-7 2*200Gbps: 30.946 : 31.770
>>>   - intel E810 1*100Gbps: 49.386 : 46.366
>>>   - intel E810 2*200Gbps (2CQ-DA2): 47.979 : 49.503
>>> ------------------------------------------------
>>> TEST MACSWAP 256B: <NIC: Before: After>
>>>   - mellanox CX-7 2*200Gbps: 32.480 : 33.150
>>>   - intel E810 1 * 100Gbps: 45.29 : 44.571
>>>   - intel E810 2 * 200Gbps (2CQ-DA2): 45.033 : 45.117
>>> ------------------------------------------------
>>>
>>> Platform-2: AMD EPYC 9554 @3.1GHz, no boost
>>>
>>> ------------------------------------------------
>>> TEST IO 64B: baseline <NIC : MPPs>
>>>   - intel E810 2*200Gbps (2CQ-DA2): 82.49
>>> ------------------------------------------------
>>> <NIC intel E810 2*200Gbps (2CQ-DA2): Before : After>
>>> TEST MACSWAP: 1Q 1C1T
>>>   64B: : 45.0 : 45.54
>>> 128B: : 44.48 : 44.43
>>> 256B: : 42.0 : 41.99
>>> +++++++++++++++++++++++++
>>> TEST MACSWAP: 2Q 2C2T
>>>   64B: : 59.5 : 60.55
>>> 128B: : 56.78 : 58.1
>>> 256B: : 41.85 : 41.99
>>> ------------------------------------------------
>>>
>>> Signed-off-by: Vipin Varghese<vipin.varghese@amd.com>
>>>
>> Hi Bruce, John,
>>
>> Can you please help testing macswap performance with this patch on Intel
>> platforms, to be sure it is not causing regression?
>>
> Hi Ferruh,
>
> We can try and get some Intel numbers for you, but I think at this point it
> is better deferred to 24.11 due to lack of discussion and analysis of the
> numbers. This is because the numbers above already show that it is causing
> regressions - in fact many of the regressions are larger than the benefits
> shown. This may be acceptable, but it would imply that we shouldn't be too
> hasty in applying the patch.
>
> Regards,
> /Bruce

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