Xref: utzoo comp.sys.ibm.pc:28889 comp.sys.amiga:33890
Path: utzoo!attcan!uunet!cs.utexas.edu!husc6!ogccse!blake!uw-beaver!ssc-vax!coy
From: coy@ssc-vax.UUCP (Stephen B Coy)
Newsgroups: comp.sys.ibm.pc,comp.sys.amiga
Subject: Re: OS/2 vs AmigaDOS
Message-ID: <2656@ssc-vax.UUCP>
Date: 16 May 89 04:38:31 GMT
References: <2134@iitmax.IIT.EDU> <5625@microsoft.UUCP> <5664@microsoft.UUCP> <2954@rti.UUCP>
Organization: Boeing Aerospace Corp., Seattle WA
Lines: 76

In article <2954@rti.UUCP>, bcw@rti.UUCP (Bruce Wright) writes:
> I haven't seen the MIPS issue that you refer to, and I haven't done any
> benchmarks on OS/2, but there are a few things you have to be very
> careful about when you read "benchmark" articles from the general press:
> 
>     1)	In comparing a multitasking and a singletasking operating system,
> 	it is not fair to compare the multitasking system running several
> 	{jobs, tasks, processes depending on the OS terminology} unless
> 	the tasks are completely heterogeneous.

True.  The benchmark I was refering to was dhrystones.  The actual
numbers I have posted in my previous article.  I understand that
even "at rest" a multitasking OS usually has at least a handful of
processes active.  Fine.  But when this system overhead eats up 40
to 50% of a 25Mhz 386 I start to have questions.

re "general press" the people at MIPS magazine seem to have their heads on
straight.  I've been told that their benchmarking suite was
discussed in some detail in their February issue.

>     2)	In general, you should not expect that the multitasking system will
> 	run equally fast as the single tasking system given the same amount
> 	of memory.

The systems benchmarked were all "fully loaded" and as such had
plenty of memory to run the dhrystones benchmark with megs to spare.

>     3)	What you are buying with multitasking is the ability to use several
> 	resources at once (like run a compile in the background while you
> 	edit a file in the foreground) and (possibly, depending on your
> 	application) an ability to have several tasks waiting for various
> 	events.  All this does take memory, and some CPU time.  The hope is
> 	that by allowing different processes to complement their use of
> 	resources that more total work can get done;  but you can almost
> 	always set up pathological cases.

I understand the benefits of multi-tasking.  My Amiga has been
cranking along just fine since Oct '85, multi-tasking all the way.
Running the Dhrystones benchmark on an empty machine is not a
pathological case by a long shot.  Although the MIPS benchmarks sure
make running it under OS/2 seem like a pathetic case.  (Cheap shot,
I know.  Sorry  :-)

>     4)	If they are comparing OS/2 using the Presentation Manager then I
> 	expect it would be slower ... without significant hardware assists
> 	it's hard for a graphics based system to compete with a text based
> 	system.

Dhrystones is not I/O dependent.  Next.

>     5)	It is quite possible for a benchmark to home in on a particular
> 	bottleneck on the system and make the system look much worse than
> 	it would look in a real environment.  Many of the authors of the
> 	benchmark "results" that you see in magazines don't seem to have
> 	a very good grasp of this.

Ok, so what is it about OS/2 that causes it to slow down dhrystones
so much?  Hint:  the actual number of cycles executed by dhrystones
under each OS is about the same depending on compiler variations.
The "bottleneck" is not the benchmark picking on the system but the
system being too fat.

> Maybe someone who has done more scientific benchmarking on the system can
> address the specific questions about the actual speed of OS/2.
> 
> 						Bruce C. Wright

I'm sorry if this came off as a flame but the tone of your response
implied that I was too ignorant to know what I was talking about and
this offended me a touch.

I too would like to see some other comparisons done.  If anyone has
any, please post.

Stephen Coy
uw-beaver!ssc-vax!coy