Re: [dpdk-dev] [PATCH v1 2/3] app/crypto-perf: honour cryptodev's min headroom/tailroom

["De Lara Guarch, Pablo" <pablo.de.lara.guarch@intel.com>]

> -----Original Message-----
> From: De Lara Guarch, Pablo
> Sent: Tuesday, July 10, 2018 12:08 PM
> To: 'Anoob Joseph' <anoob.joseph@caviumnetworks.com>; Doherty, Declan
> <declan.doherty@intel.com>
> Cc: Akhil Goyal <akhil.goyal@nxp.com>; Ankur Dwivedi
> <ankur.dwivedi@caviumnetworks.com>; Jerin Jacob
> <jerin.jacob@caviumnetworks.com>; Narayana Prasad
> <narayanaprasad.athreya@caviumnetworks.com>; dev@dpdk.org
> Subject: RE: [PATCH v1 2/3] app/crypto-perf: honour cryptodev's min
> headroom/tailroom
> 
> 
> 
> > -----Original Message-----
> > From: Anoob Joseph [mailto:anoob.joseph@caviumnetworks.com]
> > Sent: Wednesday, July 4, 2018 2:56 PM
> > To: Doherty, Declan <declan.doherty@intel.com>; De Lara Guarch, Pablo
> > <pablo.de.lara.guarch@intel.com>
> > Cc: Anoob Joseph <anoob.joseph@caviumnetworks.com>; Akhil Goyal
> > <akhil.goyal@nxp.com>; Ankur Dwivedi
> > <ankur.dwivedi@caviumnetworks.com>; Jerin Jacob
> > <jerin.jacob@caviumnetworks.com>; Narayana Prasad
> > <narayanaprasad.athreya@caviumnetworks.com>; dev@dpdk.org
> > Subject: [PATCH v1 2/3] app/crypto-perf: honour cryptodev's min
> > headroom/tailroom
> >
> > Crypto dev would specify its headroom and tailroom requirement and the
> > application is expected to honour this while creating buffers.
> >
> > Signed-off-by: Anoob Joseph <anoob.joseph@caviumnetworks.com>
> 
> ...
> 
> > --- a/app/test-crypto-perf/cperf_test_common.c
> > +++ b/app/test-crypto-perf/cperf_test_common.c
> 
> ...
> 
> > fill_multi_seg_mbuf(struct rte_mbuf *m, struct rte_mempool *mp,
> >  		m->buf_iova = next_seg_phys_addr;
> >  		next_seg_phys_addr += mbuf_hdr_size + segment_sz;
> >  		m->buf_len = segment_sz;
> > -		m->data_len = segment_sz;
> > +		m->data_len = data_len;
> >
> > -		/* No headroom needed for the buffer */
> > -		m->data_off = 0;
> > +		/* Use headroom specified for the buffer */
> > +		m->data_off = headroom;
> 
> Headroom is only applicable for the first segment/s.
> This is adding headroom in all the segments, which looks wrong.
> 

I think "max_size" needs to be recalculated in "cperf_alloc_common_memory",
adding headroom and tailroom size, which will potentially increase the number of segments required.
Then, headroom size needs to be checked in case it is bigger than segment size, so data might need to start in the next segment.
Similar thing for tailroom.

Thanks,
Pablo