From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH 1/3 v2] librte_hash: Fix unsupported instruction `crc32' in i686 platform Date: Thu, 19 Mar 2015 09:10:06 +0100 Message-ID: <2427100.51HZplg4KW@xps13> References: <1425561339-13300-2-git-send-email-michael.qiu@intel.com> <9442704.dXlXz1iyK3@xps13> <533710CFB86FA344BFBF2D6802E60286D1603B@SHSMSX101.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: dev-VfR2kkLFssw@public.gmane.org To: "Qiu, Michael" Return-path: In-Reply-To: <533710CFB86FA344BFBF2D6802E60286D1603B-0J0gbvR4kThpB2pF5aRoyrfspsVTdybXVpNB7YpNyf8@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" 2015-03-19 02:00, Qiu, Michael: > On 3/8/2015 2:39 AM, Thomas Monjalon wrote: > > 2015-03-06 01:39, Qiu, Michael: > >> On 3/6/2015 1:11 AM, Thomas Monjalon wrote: > >>> 2015-03-06 00:55, Michael Qiu: > >>>> CC rte_hash.o > >>>> Error: unsupported instruction `crc32' > >>>> > >>>> The root cause is that i686 platform does not support 'crc32q' > >>>> Need make it only available in x86_64 platform > >>>> > >>>> Signed-off-by: Michael Qiu > >>>> --- > >>>> v2 --> v1: > >>>> Make crc32 instruction only works in X86 platform > >>>> lib/librte_hash/rte_hash_crc.h | 12 ++++++++++++ > >>>> 1 file changed, 12 insertions(+) > >>>> > >>>> diff --git a/lib/librte_hash/rte_hash_crc.h b/lib/librte_hash/rte_hash_crc.h > >>>> index d28bb2a..c0a789e 100644 > >>>> --- a/lib/librte_hash/rte_hash_crc.h > >>>> +++ b/lib/librte_hash/rte_hash_crc.h > >>>> @@ -364,6 +364,7 @@ crc32c_2words(uint64_t data, uint32_t init_val) > >>>> return crc; > >>>> } > >>>> > >>>> +#if defined RTE_ARCH_I686 || defined RTE_ARCH_X86_64 > >>>> static inline uint32_t > >>>> crc32c_sse42_u32(uint32_t data, uint32_t init_val) > >>>> { > >>>> @@ -373,7 +374,9 @@ crc32c_sse42_u32(uint32_t data, uint32_t init_val) > >>>> : [data] "rm" (data)); > >>>> return init_val; > >>>> } > >>>> +#endif > >>> Wouldn't it be more elegant to define a stub which returns 0 in #else > >>> in order to remove #ifdef below? > >>> Not sure, matter of taste. > >> It may be not a good idea, see rte_hash_crc_8byte(), if no crc32 > >> support, it will use crc32c_2words(), if we define a stub which returns > >> 0 in #else, then we need always check the return value whether it is > >> none-zero otherwise need fallback. > > I don't think so. > > The stub won't never been called because they are protected by the cpuflag > > condition. > > Hi, Thomas > > Indeed what I concerned occurs, when compile target i686 in X86_64 > platform, it will call the stub function Oh, you mean compiling for i686 and run it in x86_64 target, so the stub for crc32c_sse42_u64 is called? > Then, should I make a patch to fix, change the code as this one(V2) > Another choice is you could revert V3 and merge V2. > Or if have other solution? It's probably saner to submit a fix you have tested with ifdef like in v2. Thanks