The APIs that currently support alignment are odp_buffer_pool_create() and odp_shm_reserve()
On Tue, Dec 9, 2014 at 7:03 AM, Bill Fischofer <bill.fischo...@linaro.org> wrote: > That makes sense. I'll add those additional CONFIG vars to the v3 patch. > I don't see a use case for alignments above 4K for RAW buffers so that's a > reasonable upper limit, however I suspect some implementations may have > problems with that. If a platform has a HW buffer manager that uses 512 > byte blocks, they are going to be 512-byte aligned and it's meaningless to > try to ask for a higher alignment. > > On Tue, Dec 9, 2014 at 6:54 AM, Savolainen, Petri (NSN - FI/Espoo) < > petri.savolai...@nsn.com> wrote: > >> >> >> >> >> *From:* lng-odp-boun...@lists.linaro.org [mailto: >> lng-odp-boun...@lists.linaro.org] *On Behalf Of *ext Bill Fischofer >> *Sent:* Tuesday, December 09, 2014 1:08 PM >> *To:* lng-odp-forward >> *Subject:* [lng-odp] Alignment question >> >> >> >> A number of APIs support a buf_align parameter but we haven't been >> terribly precise about limits on this, so some questions for Petri. >> >> >> >> I think only buffer_pool_create has alignment parameter. >> >> >> >> With buf_align being defined as uint32_t in theory we can specify >> alignments up to 2GB. >> >> >> >> 1. MAY implementations impose a lower upper limit on the alignments they >> support? >> >> >> >> ODP_CONFIG_BUFFER_ALIGN_MAX (4*1024) ? >> >> >> >> >> >> 2. If so, what is the minimum acceptable upper alignment limit? We've >> specified that buffers MUST be at minimum 8 byte aligned but is that >> sufficient? >> >> >> >> ODP_CONFIG_BUFFER_ALIGN_MIN 8 ? >> >> >> >> 3. If implementations MAY impose an upper alignment limit below 2GB, what >> SHOULD happen if an application requests an alignment above this limit? >> Fail the request? Saturate at the implementation-defined max alignment? >> >> >> >> It should fail. User requests minimum alignment, implementation can round >> up. >> >> >> >> -Petri >> >> >> > >
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