> -----Original Message----- > From: Jerin Jacob [mailto:jerin.jacob at caviumnetworks.com] > Sent: Thursday, December 03, 2015 12:17 PM > To: Ananyev, Konstantin > Cc: Thomas Monjalon; dev at dpdk.org; viktorin at rehivetech.com > Subject: Re: [dpdk-dev] [PATCH 3/4] eal/arm: Enable lpm/table/pipeline libs > > On Thu, Dec 03, 2015 at 11:02:07AM +0000, Ananyev, Konstantin wrote: > > Hi Konstantin, > > > Hi Jerin, > > > > > -----Original Message----- > > > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Jerin Jacob > > > Sent: Thursday, December 03, 2015 9:34 AM > > > To: Thomas Monjalon > > > Cc: dev at dpdk.org > > > Subject: Re: [dpdk-dev] [PATCH 3/4] eal/arm: Enable lpm/table/pipeline > > > libs > > > > > > On Wed, Dec 02, 2015 at 05:57:10PM +0100, Thomas Monjalon wrote: > > > > 2015-12-02 22:23, Jerin Jacob: > > > > > On Wed, Dec 02, 2015 at 05:40:13PM +0100, Thomas Monjalon wrote: > > > > > > 2015-12-02 20:04, Jerin Jacob: > > > > > > > On Wed, Dec 02, 2015 at 09:13:51PM +0800, Jianbo Liu wrote: > > > > > > > > On 2 December 2015 at 18:39, Jerin Jacob <jerin.jacob at > > > > > > > > caviumnetworks.com> wrote: > > > > > > > > > AND they include "rte_lpm.h"(it internally includes > > > > > > > > > rte_vect.h) > > > > > > > > > that lead to multiple definition and its not good. > > > > > > > > > > > > > > > > > But you will have similar issue since "typedef int32x4_t > > > > > > > > __m128i" > > > > > > > > appears in both your patch and this header file. > > > > > > > > > > > > > > I just tested it, it won't break, back to back "typedef int32x4_t > > > > > > > __m128i" > > > > > > > is fine(unlike inline function). > > > > > > > > > > > > > > my intention to keep __m128i "as is" because changing the > > > > > > > __m128i to rte_??? > > > > > > > something would break the ABI. > > > > > > > > > > > > Isn't it already broken in 2.2? > > > > > > > > > > Does it mean, You would like to have rte_128i(or similar) kind of > > > > > abstraction to represent 128bit SIMD variable in DPDK? > > > > > > > > If you are convinced that it is the best way to write a generic code, > > > > yes. > > > > > > I grep-ed through DPDK API list to see the dependency with SIMD in API > > > definition.I see only rte_lpm_lookupx4 API has SIMD dependency in API > > > definition. > > > > > > I believe that's the root cause of the problem. IMO, The > > > better way to fix this would be to remove __m128i from API and have more > > > general representation to remove the architecture dependency from API > > > > > > something like this, > > > > > > rte_lpm_lookupx4(const struct rte_lpm *lpm, uint32_t *ip, uint16_t > > > hop[4], uint16_t defv) > > > > > > instead of > > > > > > rte_lpm_lookupx4(const struct rte_lpm *lpm, __m128i ip, uint16_t > > > hop[4], uint16_t defv) > > > > The idea for that function was that rte_lpm_lookupx4() accepts 4 IPv4 > > addresses that are: > > 1. already in 128bit register > > 2. 'prepared' - byte swap is already done for them if needed. > > > > About ways to fix __m128i dependency: as I can see x86 and arm DPDK code > > already has xmm_t typedef: > > > > $ find lib -type f | xargs grep xmm_t | grep typedef > > lib/librte_eal/common/include/arch/x86/rte_vect.h:typedef __m128i xmm_t; > > lib/librte_eal/common/include/arch/arm/rte_vect.h:typedef int32x4_t xmm_t; > > > > Why not to change rte_lpm_lookupx4() to accept xmm_t as input parameter. > > As I understand it would solve the problem, and wouldn't introduce any > > API/ABI breakage, right? > > Yes, If we have API/ABI breakage concerns. > > IMO, Now this would call for some kind of rte_vect_* abstraction load, > store, set kind of SIMD operation on xmm_t in common test code to > aviod #ifdef's in app/test/test_lpm.c
Yes, seems so. > > I guess we may not need those abstractions in > lib/librte_eal/common/include/arch/ directory. > keeping in app/test/xmmt_ops.h should be enough, right? That sounds ok to me. At least for now. For future the more generic question - do we like to have some generic layer abstraction for similar vector instrincts across different archs? >From one side it might help people writing/using vector implementation of some >stuff, from other side - there would be extra hassle creating/supporting it. Konstantin > > > > > > Konstantin > > > > > > > > Now I am not sure why this API was created like this, from l3fwd.c > > > example, it looks to accommodate the IPV4 byte swap[1]. If it's true, > > > maybe we can have eal byte swap abstraction for optimized byte swap on > > > memory for 4 IP address in one shot > > > > > > or > > > > > > Have rte_lpm_lookupx4 take an argument for byte swap or not ? > > > > > > or > > > > > > something similar? > > > > > > Thoughts ? > > > > > > [1] > > > const __m128i bswap_mask = _mm_set_epi8(12, 13, 14, 15, 8, 9, 10, 11, > > > 4, 5, 6, 7, 0, 1, 2, 3); > > > /* Byte swap 4 IPV4 addresses. */ > > > dip = _mm_shuffle_epi8(dip, bswap_mask); > > > > > > Jerin > > > > > > > I think the most important question is to know what is the best solution > > > > for performance and maintainability. The API/ABI questions will be > > > > considered > > > > after. > > > > > > > > Thanks for your involvement guys.
