Date: Sat, 12 Jun 1999 00:04:53 -0400 From: "Mikhail V. Evstiounin" <evs@telerama.com> To: <chris@calldei.com>, "David E. Cross" <crossd@cs.rpi.edu> Cc: <freebsd-hackers@FreeBSD.ORG>, <freebsd-smp@FreeBSD.ORG> Subject: Re: High syscall overhead? Message-ID: <09f401beb488$bb612390$6f27abcd@mvehpc.evs.slip.lm.com>
next in thread | raw e-mail | index | archive | help
I have installed 3.0-RELEASE FreeBSD on AMD K6, 233MHz, 128MB, ABit
Motherboard, not overclocked/
Ran this program, got the following results:
5.2u 8.5s 0:14.02 98.3% 5+171k 0+0io 0pf+0w. :-(
-----Original Message-----
From: Chris Costello <chris@calldei.com>
To: David E. Cross <crossd@cs.rpi.edu>
Cc: freebsd-hackers@FreeBSD.ORG <freebsd-hackers@FreeBSD.ORG>;
freebsd-smp@FreeBSD.ORG <freebsd-smp@FreeBSD.ORG>
Date: Friday, June 11, 1999 11:01 AM
Subject: Re: High syscall overhead?
>On Fri, Jun 11, 1999, David E. Cross wrote:
>> Just doing some performance testing and I noticed something rather
>> disturbing....
>>
>> Here is the test program:
>> int main (void)
>> {
>> int count=0;
>> for(count=0;count <10000000;++count)
>> getppid();
>>
>> return 0;
>> }
>>
>> The time on linux for this program is ~5 seconds (linux "time" reports
3.x, but
>> a wall clock clearly shows 5.x, go fig). FreeBSD reports 18.x
seconds?!. I
>> have a dual processor system and decided to parallel run them... it took
>> 52!?! seconds, linux on the same was again about 5. Looking through the
>> exception.s it appears that on entry to the kernel an MP lock is
obtained...
>> I thought we had splX(); to protect concurancy in the kernel.
>
>('sc' being the program above, compiled without optimization,
> just with cc -o sc sc.c)
>$ time ./sc
> 10.04s real 3.89s user 5.64s system
>
> I counted between around 9 and a half to 10 and a half seconds
>on my wall clock (trusty old GE, same model they have in public
>schools).
>
>Copyright (c) 1992-1999 The FreeBSD Project.
>Copyright (c) 1982, 1986, 1989, 1991, 1993
> The Regents of the University of California. All rights reserved.
>FreeBSD 4.0-CURRENT #4: Sun May 30 04:22:23 CDT 1999
> root@holly.dyndns.org:/usr/src/sys/compile/Holly
>Timecounter "i8254" frequency 1193182 Hz
>CPU: AMD-K6(tm) 3D processor (350.80-MHz 586-class CPU)
> Origin = "AuthenticAMD" Id = 0x580 Stepping=0
> Features=0x8001bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8,MMX>
>real memory = 67108864 (65536K bytes)
>sio0: system console
>avail memory = 62267392 (60808K bytes)
>
> SMP specific bug, perhaps?
>
>>
>> I am just curious what's the story with this. On some of my other tests
it is
>> clear that FreeBSD is handling concurancy much better than linux (by an
equal
>> factor actually, and on "real" tasks like real I/O handling).
>>
>> --
>> David Cross | email: crossd@cs.rpi.edu
>> Systems Administrator/Research Programmer | Web:
http://www.cs.rpi.edu/~crossd
>> Rensselaer Polytechnic Institute, | Ph: 518.276.2860
>> Department of Computer Science | Fax: 518.276.4033
>> I speak only for myself. | WinNT:Linux::Linux:FreeBSD
>>
>>
>> To Unsubscribe: send mail to majordomo@FreeBSD.org
>> with "unsubscribe freebsd-hackers" in the body of the message
>
>--
>Chris Costello <chris@calldei.com>
>This message transmitted on 100% recycled electrons.
>
>
>To Unsubscribe: send mail to majordomo@FreeBSD.org
>with "unsubscribe freebsd-smp" in the body of the message
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-smp" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?09f401beb488$bb612390$6f27abcd>