Re: [dpdk-dev] [PATCH] cryptodev: fix restore crypto op alignment and layout

[Akhil Goyal <akhil.goyal@nxp.com>]

On 3/19/2019 7:03 PM, Akhil Goyal wrote:
> Hi Konstantin,
>
> On 3/7/2019 7:43 PM, Konstantin Ananyev wrote:
>> in 18.08 new cache-aligned structure rte_crypto_asym_op was introduced.
>> As it also was included into rte_crypto_op, it caused implicit change
>> in rte_crypto_op layout and alignment: now rte_crypto_op is cahce-line
>> aligned has a hole of 40/104 bytes between phys_addr and sym/asym op.
>> It looks like unintended ABI breakage, plus such change can cause
>> negative performance effects:
>> - now status and sym[0].m_src lies on different cache-lines, so
>>     post-process code would need extra cache-line read.
>> - new alignment causes grow of the space requirements and cache-line
>>     reads/updates for structures that contain rte_crypto_op inside.
>> As there seems no actual need to have rte_crypto_asym_op cache-line
>> aligned, and rte_crypto_asym_op is not intended to be used on it's own -
>> the simplest fix is just to remove cache-line alignment for it.
>> As the immediate positive effect: on IA ipsec-secgw performance increased
>> by 5-10% (depending on the crypto-dev and algo used).
>> My guess that on machines with 128B cache-line and lookaside-protocol
>> capable crypto devices the impact will be even more noticeable.
>>
>> Fixes: 26008aaed14c ("cryptodev: add asymmetric xform and op definitions")
>>
>> Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
>> ---
>>    doc/guides/rel_notes/release_19_05.rst | 7 +++++++
>>    lib/librte_cryptodev/Makefile          | 2 +-
>>    lib/librte_cryptodev/meson.build       | 2 +-
>>    lib/librte_cryptodev/rte_crypto_asym.h | 2 +-
>>    4 files changed, 10 insertions(+), 3 deletions(-)
>>
>> diff --git a/doc/guides/rel_notes/release_19_05.rst b/doc/guides/rel_notes/release_19_05.rst
>> index c0390ca16..ec2651b65 100644
>> --- a/doc/guides/rel_notes/release_19_05.rst
>> +++ b/doc/guides/rel_notes/release_19_05.rst
>> @@ -116,6 +116,13 @@ ABI Changes
>>       Also, make sure to start the actual text at the margin.
>>       =========================================================
>>    
>> +* cryptodev: in 18.08 new structure ``rte_crypto_asym_op`` was introduced and
>> +  included into ``rte_crypto_op``. As ``rte_crypto_asym_op`` structure was
>> +  defined as cache-line aligned that caused unintended changes in
>> +  ``rte_crypto_op`` structure layout and alignment. Remove cache-line
>> +  alignment for ``rte_crypto_asym_op`` to restore expected ``rte_crypto_op``
>> +  layout and alignment.
>> +
>>    
> ABI version should be bumped in the release notes as well. I will update
> that while merging.
> Apart from that
> Acked-by: Akhil Goyal <akhil.goyal@nxp.com>
>>    Shared Library Versions
>>    -----------------------
>>
Applied to dpdk-next-crypto

Thanks.