From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bruce Richardson Subject: Re: [PATCH] Implement memcmp using AVX/SSE instructio Date: Thu, 23 Apr 2015 09:11:39 +0100 Message-ID: <20150423081138.GA8592@bricha3-MOBL3> References: <1429716828-19012-1-git-send-email-rkerur@gmail.com> <1429716828-19012-2-git-send-email-rkerur@gmail.com> <55389E44.8030603@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: dev-VfR2kkLFssw@public.gmane.org To: Pawel Wodkowski Return-path: Content-Disposition: inline In-Reply-To: <55389E44.8030603-ral2JQCrhuEAvxtiuMwx3w@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" On Thu, Apr 23, 2015 at 09:24:52AM +0200, Pawel Wodkowski wrote: > On 2015-04-22 17:33, Ravi Kerur wrote: > >+/** > >+ * Compare bytes between two locations. The locations must not overlap. > >+ * > >+ * @note This is implemented as a macro, so it's address should not be taken > >+ * and care is needed as parameter expressions may be evaluated multiple times. > >+ * > >+ * @param src_1 > >+ * Pointer to the first source of the data. > >+ * @param src_2 > >+ * Pointer to the second source of the data. > >+ * @param n > >+ * Number of bytes to compare. > >+ * @return > >+ * true if equal otherwise false. > >+ */ > >+static inline bool > >+rte_memcmp(const void *src_1, const void *src, > >+ size_t n) __attribute__((always_inline)); > You are exposing this as public API, so I think you should follow > description bellow or not call this _memcmp_ > > int memcmp(const void *s1, const void *s2, size_t n); > > The memcmp() function returns an integer less than, equal to, or greater > than > zero if the first n bytes of s1 is found, respectively, to be > less than, to > match, or be greater than the first n bytes of s2. > +1 to this point. Also, if I read your quoted performance numbers in your earlier mail correctly, we are only looking at a 1-4% performance increase. Is the additional code to maintain worth the benefit? /Bruce > -- > Pawel