On 11/11/2015 09:45 AM, Savolainen, Petri (Nokia - FI/Espoo) wrote: > >> -----Original Message----- >> From: lng-odp [mailto:lng-odp-boun...@lists.linaro.org] On Behalf Of >> EXT Nicolas Morey-Chaisemartin >> Sent: Tuesday, November 10, 2015 5:13 PM >> To: Zoltan Kiss; linaro-toolch...@lists.linaro.org >> Cc: lng-odp >> Subject: Re: [lng-odp] Runtime inlining >> >> As I said in the call last week, the problem is wider than that. >> >> ODP specifies a lot of types but not their sizes, a lot of >> enums/defines (things like ODP_PKTIO_INVALID) but not their value >> either. >> For our port a lot of those values were changed for >> performance/implementation reason. So I'm not even compatible between >> one version of our ODP port and another one. >> >> The only way I can see to solve this is for ODP to fix the size of all >> these types. >> Default/Invalid values are not that easy, as a pointer would have a >> completely different behaviour from structs/bitfields >> >> Nicolas >> > Type sizes do not need to be fixed in general, but only when an application > is build for binary compatibility (the use case we are talking here). Binary > compatibility and thus the fixed type sizes are defined per ISA. > > We can e.g. define a configure target (for our reference implementation == > linux-generic) "--binary-compatible=armv8.x" or "--binary-compatible=x86_64". > When you build your application with that option, "platform dependent" types > and constants would be fixed to pre-defined values specified in (new) ODP API > arch files. > > So instead of building against > odp/platform/linux-generic/include/odp/plat/queue_types.h ... > > typedef ODP_HANDLE_T(odp_queue_t); > #define ODP_QUEUE_INVALID _odp_cast_scalar(odp_queue_t, 0) > #define ODP_QUEUE_NAME_LEN 32 > > > ... you'd build against odp/arch/armv8.x/include/odp/queue_types.h ... > > typedef uintptr_t odp_queue_t; > #define ODP_QUEUE_INVALID ((uintptr_t)0) > #define ODP_QUEUE_NAME_LEN 64 > > > ... or odp/arch/x86_64/include/odp/queue_types.h > > typedef uint64_t odp_queue_t; > #define ODP_QUEUE_INVALID ((uint64_t)0xffffffffffffffff) > #define ODP_QUEUE_NAME_LEN 32 > > > For highest performance on a fixed target platform, you'd still build against > the platform directly > > odp/platform/<soc_vendor_xyz>/include/odp/plat/queue_types.h > > typedef xyz_queue_desc_t * odp_queue_t; > #define ODP_QUEUE_INVALID ((xyz_queue_desc_t *)0xdeadbeef) > #define ODP_QUEUE_NAME_LEN 20 > > > -Petri >
It still means that you need to enforce a type for all ODP implementation on a given arch. Which could be problematic. As a precise example: the way handles are used now for odp_packet_t brings some useful features for checks and memory savings, but performance wise, they are a "disaster". One of the first thing I did was to switch them to pointers. And if I wanted a high perf linux x86_64 implementation, I'd probably do the same. Nicolas _______________________________________________ lng-odp mailing list lng-odp@lists.linaro.org https://lists.linaro.org/mailman/listinfo/lng-odp
