From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,f03ffdf470e3c559 X-Google-Attributes: gid103376,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news1.google.com!border1.nntp.dca.giganews.com!border2.nntp.dca.giganews.com!nntp.giganews.com!cyclone1.gnilink.net!spamkiller.gnilink.net!gnilink.net!nwrddc01.gnilink.net.POSTED!c9e1c1fe!not-for-mail From: Jeffrey Creem User-Agent: Thunderbird 2.0.0.17 (Windows/20080914) MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Interesting performance quirk. References: <4903c066$0$28676$4d3efbfe@news.sover.net> In-Reply-To: <4903c066$0$28676$4d3efbfe@news.sover.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Message-ID: Date: Sun, 26 Oct 2008 02:15:01 GMT NNTP-Posting-Host: 71.181.45.230 X-Complaints-To: abuse@verizon.net X-Trace: nwrddc01.gnilink.net 1224987301 71.181.45.230 (Sat, 25 Oct 2008 22:15:01 EDT) NNTP-Posting-Date: Sat, 25 Oct 2008 22:15:01 EDT Xref: g2news1.google.com comp.lang.ada:2497 X-Original-Bytes: 2071 Date: 2008-10-26T02:15:01+00:00 List-Id: Peter C. Chapin wrote: > Now the interesting part. My main development system is a Windows XP > laptop. On this system my "optimized" Blowfish benchmark encrypts or > decrypts at about 11 MB/s (curiously decryption is a little faster than > encryption, which seems odd). It also happens that I have OpenSUSE 10.2 > Linux running on the same box in a VMware virtual machine. In that > environment my benchmark encrypts or decrypts at fully 27 MB/s. It's > over twice as fast! I'm using GNAT GPL 2008 in both cases with the same > compiler options and exactly the same source code. I'm even using the > same basic hardware although, as I said, one of my systems---the faster > one---is a virtual machine. > Hmm, certainly seems odd. I wonder if one of these two versions was configured differently and thus has a different set of default options. It seems like it would be interesting to quickly disassembly the inner loop on the two machines and see if anything jumps out. From the description, it seems like you should be getting identical code. Or maybe you just need to keep nesting the VMs until this code runs at 200 GB/sec :)