[dpdk-dev] [PATCH] vhost: adaptively batch small guest memory copies

Tiwei Bie tiwei.bie at intel.com
Fri Sep 8 12:38:29 CEST 2017


On Fri, Sep 08, 2017 at 03:41:08PM +0800, Yuanhan Liu wrote:
> On Thu, Aug 24, 2017 at 10:19:39AM +0800, Tiwei Bie wrote:
> > This patch adaptively batches the small guest memory copies.
> > By batching the small copies, the efficiency of executing the
> > memory LOAD instructions can be improved greatly, because the
> > memory LOAD latency can be effectively hidden by the pipeline.
> > We saw great performance boosts for small packets PVP test.
> > 
> > This patch improves the performance for small packets, and has
> > distinguished the packets by size. So although the performance
> > for big packets doesn't change, it makes it relatively easy to
> > do some special optimizations for the big packets too.
> 
> The number showed in other replies looks really impressive. Great work!
> This patch also looks good to me. I have one minor comment though.
> 
> [...]
> > +/*
> > + * Structure contains the info for each batched memory copy.
> > + */
> > +struct burst_copy_elem {
> > +	void *dst;
> > +	void *src;
> > +	uint32_t len;
> > +	uint64_t log_addr;
> > +};
> 
> Like the title says, it's more about batch (but not burst). Also, it's
> not a good idea to mix burst and batch. I'd suggest you to use the term
> "batch" consistently.
> 

Okay, I'll change it. Thank you! :-)

Best regards,
Tiwei Bie


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