From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Sune Subject: Re: Non-argv dependant rte_eal_init() call Date: Thu, 01 Aug 2013 18:13:17 +0200 Message-ID: <51FA891D.2070702@bisdn.de> References: <51FA80BF.2020801@bisdn.de> <201308011801.08070.thomas.monjalon@6wind.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: dev-VfR2kkLFssw@public.gmane.org To: Thomas Monjalon Return-path: In-Reply-To: <201308011801.08070.thomas.monjalon-pdR9zngts4EAvxtiuMwx3w@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" Dear Thomas, Regarding the MAIN, then I understand is not really necessary for Linux user-space applications, and that is there in the examples because they can run both baremetal and userspace... this is fine. Regarding the rte_eal_init(), if the concern is the number of parameters and backwards compatibility, a typical solution is to create a struct containing the parameters: typedef struct eal_init_params{ uint64_t coremask; unsigned int num_of_cache_lines; /* Add here more parmeters in future versions... */ }eal_init_params_t; int rte_eal_init(eal_init_params_t* params); Therefore the user code, is always backwards compatible (provided that is properly recompiled). In any case, and besides the struct approach, I think is more elegant to add a parameter to a function call if you jump to a newer version of the DPDK, than having to create a fake C string array or forcing the applications to add extra DPDK parameters in the executable. Just my 2 cents ;) Best marc On 01/08/13 18:01, Thomas Monjalon wrote: > Hello, > > 01/08/2013 17:37, Marc Sune : >> In our case, we are right now simply faking the argv, which is a little >> bit ugly: >> >> //... >> 37 const char* argv[EAL_ARGS] = {"./fake", "-c",CORE_MASK, >> "-n",NUM_CACHE_LINES, ""}; >> //... >> 53 ret = rte_eal_init(EAL_ARGS, (char**)argv); >> 54 if (ret < 0) >> 55 rte_exit(EXIT_FAILURE, "rte_eal_init failed"); >> //... >> > You should provide a better binary name because in your example, your logs > will be prefixed with "fake" which is, I agree with you, a little bit ugly ;) > >> IMHO it would make more sense to have actually two calls, adding a >> library-like initialization. Something like: >> >> >> /* >> * In the comments a warning that this should be called at the very >> beginning of the program. >> *... >> */ >> int rte_eal_init(eal_coremask_t core_mask, unsigned int num_of_lines >> /*More parameters here...*/); >> >> /* >> * >> */ >> int rte_eal_init_argv(int argc, char **argv); >> >> > The problem with your proposal is that the number of options is static. > So when adding a new option in future releases, all the applications should be > updated to give a (probably null) value for this new option. > Not sure it is an improvement. > >> Btw, the same applies to the mangling of the main() (MAIN) routine. Is >> this really necessary? Isn't it enough to clearly state in the >> documentation that certain API calls need to be made on the very >> beginning of the application? > Not sure to understand this point. > MAIN is only defined in examples for the bare-metal use case. > What is the link with the API ? >