Date: Mon, 4 May 1998 15:20:56 +0800 From: Joerg Micheel <joerg@krdl.org.sg> To: Greg Lehey <grog@lemis.com> Cc: John-Mark Gurney <gurney_j@resnet.uoregon.edu>, FreeBSD Hackers <hackers@FreeBSD.ORG> Subject: Re: Context switch time Message-ID: <19980504152056.47011@krdl.org.sg> In-Reply-To: <19980504155242.P4777@freebie.lemis.com>; from Greg Lehey on Mon, May 04, 1998 at 03:52:42PM %2B0930 References: <Pine.BSF.3.96.980425041329.28708A-100000@fledge.watson.org> <19980425034313.55993@hydrogen.nike.efn.org> <19980504143736.L4777@freebie.lemis.com> <19980503222303.36966@hydrogen.nike.efn.org> <19980504140442.52763@krdl.org.sg> <19980504155242.P4777@freebie.lemis.com>
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Greg, maybe, we should exchange our test programs :-). On Mon, May 04, 1998 at 03:52:42PM +0930, Greg Lehey wrote: > On Mon, 4 May 1998 at 14:04:42 +0800, Joerg Micheel wrote: > > On Sun, May 03, 1998 at 10:23:03PM -0700, John-Mark Gurney wrote: > >> Greg Lehey scribbled this message on May 4: > >>> On Sat, 25 April 1998 at 3:43:13 -0700, John-Mark Gurney wrote: > >>> > >>> Strange. This is what I get from a program that repeatedly calls > >>> getpid() on my K6/233: > > > > These numbers might not that much depend on processor type/speed. What > > about memory/cache speed ? Chipset ? Comments ? > > I think they have quite a strong relationship with processor power. > In particular, the P5/133 and your P5/200 seem to handle about 3500 > syscalls/MHz. The P5/75 is presumably slower because of the missing > cache, and I've noticed before that the K6 isn't as much faster at > this sort of thing as I would expect--suggestions for the reasons are > welcome. One could be that it's an Inten TX board with 96 MB, of > which only 64 MB are cached, but it seems to match up with John-Mark's > observations. Here is the Dell OptiPlex GXa, a 300 MHz PentiumPro: CPU: Pentium Pro (298.00-MHz 686-class CPU) Origin = "GenuineIntel" Id = 0x634 Stepping=4 Features=0x80f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,<b11>,MTRR,PGE,MCA,CMOV> real memory = 67108864 (65536K bytes) avail memory = 62709760 (61240K bytes) procs memory page disks faults cpu r b w avm fre flt re pi po fr sr s0 c0 in sy cs us sy id 1 0 0 3632 15368 1 0 0 0 0 0 0 0 260 802901 19 36 64 0 1 0 0 3632 15368 1 0 0 0 0 0 0 0 235 730504 14 41 59 0 1 0 0 3632 15368 1 0 0 0 0 0 0 0 235 730576 14 33 67 0 1 0 0 3632 15368 1 0 0 0 0 0 0 0 237 730535 15 39 61 0 1 0 0 3992 15368 1 0 0 0 0 0 0 0 238 730391 16 41 59 0 1 0 0 3992 15368 1 0 0 0 0 0 0 0 238 730400 14 36 64 0 1 0 0 3992 15368 1 0 0 0 0 0 0 0 255 729675 14 42 58 0 This trace was taken remotely by rlogin. I tried the same again by redirecting stdout to a file on /tmp: procs memory page disks faults cpu r b w avm fre flt re pi po fr sr s0 c0 in sy cs us sy id 1 0 0 4244 15360 1 0 0 0 0 0 0 0 234 694430 12 33 67 0 1 0 0 4244 15360 1 0 0 0 0 0 0 0 234 695129 12 41 59 0 1 0 0 4244 15360 1 0 0 0 0 0 0 0 235 695109 12 45 55 0 1 0 0 4244 15360 1 0 0 0 0 0 0 0 232 695202 12 30 70 0 1 0 0 4244 15360 1 0 0 0 0 0 0 0 234 695150 12 41 59 0 1 0 0 4244 15360 1 0 0 0 0 0 0 0 231 698924 13 43 57 0 So - I wrote a program to get rid of IO dependencies and process interference. Here is the result for: P5/200: 1391351 usecs/1000000 calls, 718725 calls/sec 1390469 usecs/1000000 calls, 719181 calls/sec 1390228 usecs/1000000 calls, 719306 calls/sec 1390017 usecs/1000000 calls, 719415 calls/sec 1390116 usecs/1000000 calls, 719364 calls/sec 1411161 usecs/1000000 calls, 708636 calls/sec 1390442 usecs/1000000 calls, 719195 calls/sec 1397887 usecs/1000000 calls, 715365 calls/sec 1468439 usecs/1000000 calls, 680995 calls/sec 1397388 usecs/1000000 calls, 715620 calls/sec PP6/300: 1378083 usecs/1000000 calls, 725645 calls/sec 1375760 usecs/1000000 calls, 726870 calls/sec 1582910 usecs/1000000 calls, 631747 calls/sec 1375810 usecs/1000000 calls, 726844 calls/sec 1375916 usecs/1000000 calls, 726788 calls/sec 1375900 usecs/1000000 calls, 726797 calls/sec 1375866 usecs/1000000 calls, 726814 calls/sec 1375858 usecs/1000000 calls, 726819 calls/sec 1375785 usecs/1000000 calls, 726857 calls/sec 1375755 usecs/1000000 calls, 726873 calls/sec You seem to be right in some way, but the result does not directly suggest that there is a 1:1 relationship with processor speed, at least not on the high-end machines. The performance gain on the 300 MHz machine is VERY slight (around 1%). Unfortunately, I currently don't have any slower machines around. I might try on my 133MHz Pentium at home tonight. Joerg -- Joerg B. Micheel Email: <joerg@krdl.org.sg> SingAREN Technology Center Phone: +65 7705577 Kent Ridge Digital Labs Fax: +65 7795966 11 Science Park Road Pager: +65 96016020 Singapore Science Park II Plan: Troubleshooting ATM 117685 Singapore Networks and Applications To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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