RE: [PATCH v10 1/2] mempool cache: add zero-copy get and put functions

["Morten Brørup" <mb@smartsharesystems.com>]

> From: Thomas Monjalon [mailto:thomas@monjalon.net]
> Sent: Wednesday, 7 June 2023 12.32
> 
> 24/02/2023 19:10, Kamalakshitha Aligeri:
> > From: = Morten Brørup <mb@smartsharesystems.com>
> 
> There is an equal sign inserted above.

Could be removed while applying?

> 
> >
> > Zero-copy access to mempool caches is beneficial for PMD performance, and
> > must be provided by the mempool library to fix [Bug 1052] without a
> > performance regression.
> >
> > [Bug 1052]: https://bugs.dpdk.org/show_bug.cgi?id=1052
> >
> > Bugzilla ID: 1052
> 
> It would be fun if the bug content was a link to an email :)
> More fun: refer to a place which will be deleted in some time.
> Really, please explain the problem in the patch.
> You can refer to the Bugzilla, but the idea must be in the patch.
> Then no need for the full link.
> 
> 

OK, how about this:

Zero-copy access to mempool caches is beneficial for PMD performance.

Furthermore, having a zero-copy mempool API is considered a precondition for fixing a certain category of bugs, present in some PMDs: For performance reasons, some PMDs had bypassed the mempool API in order to achieve zero-copy access to the mempool cache. This can only be fixed in those PMDs without a performance regression if the mempool library offers zero-copy access APIs, so the PMDs can use the proper mempool API instead of copy-pasting code from the mempool library. Furthermore, the copy-pasted code in those PMDs has not been kept up to date with the improvements of the mempool library, so when they bypass the mempool API, mempool trace is missing and mempool statistics is not updated.

Bugzilla ID: 1052