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Uh. The core is better. Try benching a Barton (32 bit) next to a P4, you'll see. I think it takes something like a 266MHz barton to clock with a 1GHz P4. I estimate a clawhammer core at probably ~1.25-1.5x faster than a Barton core; but with the extra registers and with the code in long mode (built - -march=k8), the total execution speed including those from compiler gains is about 2.0x. PIC has no overhead (something like 0.01%), where it has something like 0.99002% on x86. All you need is a compiler that spits out x86-64 code. C is high level; you don't do stupid shit like code for a CPU. Robert L Cochran wrote: > D. Richard Hipp wrote: > >> On Fri, 2005-01-21 at 20:56 -0500, Robert L Cochran wrote: >> >> >>> Does this version take advantage of 64-bit cpu's like the AMD Athlon >>> 64? >> >> >> I don't know. What do you mean by "take advantage of"? >> What does a 64-bit CPU do that you can't do with a 32-bit CPU? >> >> There are a few limits in SQLite that are based on the number of >> bits in an integer. For example, you can't have more than 32 >> tables in a join. Except on a 64-bit machine where you can have >> 64 tables in a join. Is that what you mean by taking advantage >> of a 64-bit CPU? But note that we could get 32-bit CPUs to provide 64 >> tables in a join just by changing a single line of >> code, namely changing >> >> typedef unsigned int Bitmask; >> >> into >> >> typedef unsigned long long int Bitmask; >> >> So how does that really "take advantage of" the 64-bitness of >> some CPUs? >> >> I hear a lot of excitement about 64-bit CPUs which I really >> do not understand. Please explain this to me. >> >> >> > I don't know how to explain this "excitement" myself, except through > examples that might bore you because I don't know the details of how to > write a program that takes advantage of a 64 bit cpu. The excitement is > mainly about speed, I would say. To make compiled software harness that > speed, it may be that only a compiler flag has to be turned on; I'm not > real sure and should research it. But here are some examples: > > 1. My wife, on her 32 bit Intel laptop, running Microsoft Access, finds > her system slowed down to a crawl whenever she works with one table that > has 109,000 rows. This is just the beginning of the huge tables she > creates. She has a bunch of others. > > I moved this table to my Athlon 64 machine and converted it to the Linux > x86_64 version of MySQL version 4.1.7. Then I queried the database > using a PHP script to "select distinct" from 3 different columns and > stuff the result sets into HTML select tags so that the client can pick > valid column values for those columns. 3 queries, 109,000 rows...and > they executed so fast the web page seems to come up instantly. > > I plan to try this same query with SQLite as soon as I have time. > > 2. I can install Fedora Core x86_64 in about 25 minutes on my Athlon > machine. On a 32 bit Intel machine, I can take a lunch hour break and > the install still might not be finished, depending on the machine's > resources. And these are all NFS image installs. I don't do them from CD > or DVD any longer. Using the network is faster. > > 3. I generally enjoy blindingly fast compile times when I have to do > compiles of large codebases such as PHP from source. I haven't yet tried > compiling Mozilla on this machine, but I'll get there -- I've done it on > my Pentium machines and it takes a minimum of 45 minutes to complete. > > The sum total is that speaking for myself, I won't go back to an Intel > 32 bit system if I can help it. 64 bit systems are fast! They save a lot > of time. > > Perhaps I'm making a stupid point, but perhaps there is a compiler > switch you can turn on somewhere (or maybe the configure script in the > *tar.gz source code already does it) that optimizes for a 64 bit system. > Hmmm, perhaps I can rerun autoconf and libtool and get this magic to > happen. > > Bob Cochran > Greenbelt, Maryland > > > > > - -- All content of all messages exchanged herein are left in the Public Domain, unless otherwise explicitly stated. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFB8eFThDd4aOud5P8RAhAdAKCJmrtQyZ3Q5CT1TbVPuh4rid5PowCdG5NN PcEmRjZ5lSbhtHu3A0q1efk= =A4WB -----END PGP SIGNATURE-----
