From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 15528 invoked from network); 15 Aug 2021 16:49:19 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 15 Aug 2021 16:49:19 -0000 Received: (qmail 19769 invoked by uid 550); 15 Aug 2021 16:49:16 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 19751 invoked from network); 15 Aug 2021 16:49:16 -0000 Date: Sun, 15 Aug 2021 12:49:04 -0400 From: Rich Felker To: Stefan Kanthak Cc: Szabolcs Nagy , musl@lists.openwall.com Message-ID: <20210815164903.GJ13220@brightrain.aerifal.cx> References: <0C6AAAD55DA44C6189B2FF4F5FB2C3E7@H270> <20210810213455.GB37904@port70.net> <20210814234612.GH37904@port70.net> <367A4018B58A4E308E2A95404362CBFB@H270> <20210815145614.GI37904@port70.net> <1F3569BD7D6E45889B7518DC9BE5004B@H270> <20210815154843.GH13220@brightrain.aerifal.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Subject: Re: [musl] [PATCH #2] Properly simplified nextafter() On Sun, Aug 15, 2021 at 06:29:08PM +0200, Stefan Kanthak wrote: > Rich Felker wrote: > > > On Sun, Aug 15, 2021 at 05:19:05PM +0200, Stefan Kanthak wrote: > >> Szabolcs Nagy wrote: > >> > >> > * Stefan Kanthak [2021-08-15 09:04:55 +0200]: > >> >> Szabolcs Nagy wrote: > >> >>> you should benchmark, but the second best is to look > >> >>> at the longest dependency chain in the hot path and > >> >>> add up the instruction latencies. > >> >> > >> >> 1 billion calls to nextafter(), with random from, and to either 0 or +INF: > >> >> run 1 against glibc, 8.58 ns/call > >> >> run 2 against musl original, 3.59 > >> >> run 3 against musl patched, 0.52 > >> >> run 4 the pure floating-point variant from 0.72 > >> >> my initial post in this thread, > >> >> run 5 the assembly variant I posted. 0.28 ns/call > >> > > >> > thanks for the numbers. it's not the best measurment > >> > >> IF YOU DON'T LIKE IT, PERFORM YOUR OWN MEASUREMENT! > > > > The burden of performing a meaningful measurement is on the party who > > says there's something that needs to be changed. > > I offered you two patches which speed a rather simple function by a > measured factor of 5 and 7 respectively. IF YOU DOUBT THESE NUMBERS, > PROVIDE YOUR OWN! I really have better things to be doing than putting up with repeated toxic interactions for the sake of a supposed miniscule improvement in something nobody has identified as having any problem to begin with. If you want to engage constructively, you're welcome to. This is not it. Rich