Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!umd5!uvaarpa!mcnc!decvax!decwrl!hplabs!hpcea!hpfcdc!hpfclp!diamant From: diamant@hpfclp.HP.COM (John Diamant) Newsgroups: comp.sys.hp Subject: Re: HP825 math 15x SLOWER than 825 Message-ID: <7540009@hpfclp.HP.COM> Date: 28 Mar 88 23:14:23 GMT References: <830004@bgphp1.UUCP> Organization: HP SDE, Fort Collins, CO Lines: 104 > I have benchmarked the HP9000 series 825 using number crunching > programs and find: > > In a multitasking environment the 825 can be at least > > 15 TIMES SLOWER > ^^^^^^^^^^^^^^^ > than a 3 cpu 500!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! These are not the numbers I get. I'm not sure where all the discrepancy came from, but I ran your own, unmodified program on our 825. Our machine has more memory, and a possibly later version of the 2.0 prerelease. However, I have to point out that your benchmark was run unoptimized, which is not a good idea on a RISC-based machine. As you can see from the numbers below, the optimization (HP9000/824 HP-UX2.0opt) makes quite a difference. Compile with "-O" to get optimization. It will make much more of a difference on a RISC machine than a CISC machine, so running unoptimized on both machines is not a fair comparison (it's much less important on the 500). I wasn't sure whether you counted both user and sys time in CPU time. I did in my numbers. System time varied between .3 and 3 seconds. > The details: > > A Multitasking, CPU intensive Benchmark > > Real Time > ----------------------------------------------------------------------- > Number of Tasks > System 1 2 3 4 5 7 10 12 > ----------------------------------------------------------------------- > HP9000/500 3 CPUs 5.9 6.0 6.3 8.4 10.5 14.7 21.5 27.8 > HP900/825 HPUX1.2 29.1 58.1 87.2 116.3 145.6 205.0 291.5 350.1 HP9000/825 HP-UX2.0pre 3.0 5.3 7.8 10.4 13.2 18.3 27.4 31.7 HP9000/825 HP-UX2.0opt 2.4 4.3 6.5 9.3 9.9 13.9 18.9 23.0 > ----------------------------------------------------------------------- > CPU Time > ----------------------------------------------------------------------- > Number of Tasks > System 1 2 3 4 5 7 10 12 > ----------------------------------------------------------------------- > HP9000/500 3 CPUs 5.8 11.8 18.4 24.4 30.7 43.0 62.2 81.4 > HP900/825 HPUX1.2 29.0 57.9 87.0 116.0 144.7 202.7 288.5 346.5 HP9000/824 HP-UX2.0pre 2.7 5.2 7.7 10.3 12.9 18.2 26.2 31.1 HP9000/824 HP-UX2.0opt 2.0 3.9 5.8 7.8 9.5 13.3 18.7 19.6 > ----------------------------------------------------------------------- > NOTES: > HP9000/500: 6.5 MBytes main memory, 3 floating point CPUs, 65MByte > system, 55MByte /tmp disk, 132MByte user disk, 571MByte > data disk (Used by virtual memory), HP-UX 5.21. > > HP9000 series 825 (HP Precision Architecture, RISC machine) 16 MBytes of > main memory, single 404MByte disk drive. HP Demo, 3/23/88. > HP-UX 1.2 (Also tried it on HP-UX 2.0 pre-release with slightly > worse results). HP9000 series 825: 32 MBytes of main memory, single 404Mb disk drive. HP-UX 2.00 prerelease (probably more recent than yours). The opt entries were run through the optimizer; the other ones weren't. > ----------------------------------------------------------------------- > > WHAT DOES ALL THIS MEAN? HP advertises the 825 as a 0.5 megaflop > machine. My results show it as about a 0.03 megaflop machine. The > benchmarks were done several times wiith different machine > configurations at the Neeley sales region (Hal Shearer, hpuecoa!hals). > HP has benn very helpful but has not been able to figure out why > these results are so bad. My numbers are coming out over 10 times better than yours, so the .5 megaflop seems about right. I don't know why you were getting so much worse numbers, but I doubt the extra 16 MBytes was the difference, since your program was so small (unless it dynamically allocated a whole bunch of memory). Floating point hardware in the 825 is essentially the same as in the 500, so the multi-CPU 500 could be somewhat better. Other series 800 machines have faster floating point hardware. In operations other than floating point, the 825 is faster than the 500 (even multi-CPU). > > HP has a new 835 that is substantially faster. This benchmark has > been run at Fort Collins but I haven't gotten the results yet. I > have heard that they are faster than a 3 cpu 500 however. The 835 uses faster floating point hardware, so this would be no surprise. > > A LESSON EVERYONE SHOULD KNOW: BENCHMARK YOUR APPLICATION BEFORE YOU > BUY A MACHINE. ^^^^^^^^^^^^^^^^ This is a good lesson in any case, though I think the machine you were testing on may have been misconfigured. > > Is the 825 really that bad? Could there be a problem with the 825 > I tested. The sieve benchmark came out 12 times faster than a > single cpu 500 and all my I/O benchmarks came out very fast. I > think the 825 has a real problem with number crunching. This is not consistent with other benchmarks, so I suspect it was something with the particular 825 you tested on. John Diamant SDE UUCP: {hplabs,hpfcla}!hpfclp!diamant Hewlett-Packard Co. ARPA Internet: diamant%hpfclp@hplabs.HP.COM Fort Collins, CO