Re: [PATCH for-next 0/6] Perf and debug fixes for hfi

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Sep 13, 2021 at 09:28:20AM -0400, Dennis Dalessandro wrote:
> Here is a series of perf improvements and debug/trace fixes from Mike,
> who has this to say about the patches...
> 
> The AIP SDMA interrupt handling is inefficient:
> 
> - A slab entry is allocated for each sent packet
> 
>   This is despite the fact that there is a ring for each possible send slot
>   that could be occupied by a tx descriptor
> 
> - The interrupt handling/NAPI is lock happy has a mixed up notion of
>   producer and consumer
> 
>   The ring should be a ring of tx descriptors vs. a ring of pointers
> 
>   The consumer of descriptors should be the xmit side of the TX
> 
>   The producer of the descriptors is the SDMA interrupt handling and NAPI
>   tx completion
> 
>   There is certainly no locking required in the interrupt/TX napi tx queue
> 
>   There is no locking required in the xmit side since that is held off by NAPI
>   code
> 
> Note that these patches are also staged publicly on our GitHub site for easy
> browsing in context.
> 
> https://github.com/cornelisnetworks/linux
> 
> ---
> 
> Mike Marciniszyn (6):
>       IB/hfi1: Remove cache and embed txreq in ring
>       IB/hfi1: Get rid of hot path divide
>       IB/hfi1: Get rid of tx priv backpointer
>       IB/hfi1: Tune netdev xmit cachelines
>       IB/hfi1: Remove atomic completion count
>       IB/hfi1: Add ring consumer and producers traces

Applied to for-next, thanks

Jason