From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 39615 invoked by alias); 27 Jul 2015 23:00:42 -0000 Mailing-List: contact jit-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Post: List-Help: List-Subscribe: Sender: jit-owner@gcc.gnu.org Received: (qmail 39605 invoked by uid 89); 27 Jul 2015 23:00:41 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Checked: by ClamAV 0.98.7 on sourceware.org X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.5 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY,RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-Spam-Status: No, score=-1.5 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY,RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on sourceware.org X-Spam-Level: X-HELO: ovh.starynkevitch.net Message-ID: <55B6B80F.5030506@starynkevitch.net> Date: Thu, 01 Jan 2015 00:00:00 -0000 From: Basile Starynkevitch User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.7.0 MIME-Version: 1.0 To: Dibyendu Majumdar CC: jit@gcc.gnu.org Subject: Re: JIT compilation speed References: <1438028999.15571.92.camel@surprise> <55B6AEAE.9030806@starynkevitch.net> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2015-q3/txt/msg00117.txt.bz2 On 07/28/2015 00:52, Dibyendu Majumdar wrote: > >> So, for Dibyendu Majumdar: if the GCCJIT compilation time matters a lot to >> you in RAVI and the performance of the emitted machine code matters much >> less to you, I am afraid that GCCJIT is not the optimal library for your >> needs in RAVI (using GNU lightning or asmjit would make JIT-ing time much >> faster, at the expense of a produced machine code which runs 2 to 5 times >> slower than what GCCJIT can achieve with -O1). >> > Yes understand that - I think that libgccjit needs to be at least as > efficient as LLVM - that should be good enough. Given that today Clang/LLVM is significantly quicker to compile C code than GCC is for -O1, that won't happen very soon. GCCJIT is GCC based, so will continue to keep the heavy weight of GCC. Some people within GCC are trying to make it work faster (as a C or C++ compiler). When that would happen (and it might take years) GCCJIT will also work faster. But don't hope much of that for this 2015 year (and probably not even for 2016). GCCJIT is GCC based, so cannot be faster than GCC is! Between GCCJIT & LLVM, I guess that GCCJIT -when used with -O3- will produce slightly faster machine code than what LLVM can give, at the expense of a significantly slower JIT time. Look at GCCJIT as something GCC based, without the inconvenience of having to generate by yourself some C code. BTW, in my MELT experience, generating C code and compiling and dlopen-ing it, can be fast enough for some interactive usage. Regards. -- Basile STARYNKEVITCH http://starynkevitch.net/Basile/ email: basilestarynkevitchnet mobile: +33 6 8501 2359 8, rue de la Faiencerie, 92340 Bourg La Reine, France *** opinions {are only mine, sont seulement les miennes} ***