[openbeos] Re: Kernel status (POSIX)
- From: "Michael Phipps" <mphipps1@xxxxxxxxxxxxxxxx>
- To: openbeos@xxxxxxxxxxxxx
- Date: Thu, 03 Jan 2002 20:18:49 -0500
>> yet not impact portability whatsoever, since there's still the C
>> functions available
>> for new ports until whatever time they choose to write the optimized
>> version, or not. :)
>
>And this is the key. Write whatever you please in assembly, *as long as
>* there is a C fallback. Of course, some things have to be done in
>assembler in the kernel, and use it for that, but always provide a
>fallback everywhere else.
>-Nathan
Let me put it this way -
OTHER THAN stuff from NewOS (which is Travis' domain), anyone who wants
to use asm at all will have to justify it. There is almost never a good reason.
I would want things like a code profile showing that the code is the performance
issue, real evidence that the code CAUSES a performance issue, and to have
looked
at it as a team and decided that there is *no* other way.
Premature optimization is the root of bad coding. Moving to asm is the most
common
(that I can think of) premature optimization that people make. I use profilers
all the time
(whether -pg or some other methodology) on code that is performance crititical.
I am winding
up such a project at my full time job. Once the code was 100% complete AND
tested AND
regession testable AND documented, we work on getting it faster. Using
profiling, I have fixed
a couple, maybe as many as 5 functions and multiplied the speed of the process
by 1.5.
That, not guessing, not using folk stories and wives tales, is the way to
optimize. :-)
Travis writes most of his code in C. Only the things that need to be in asm are.
Does that make everyone comfortable? Except those who want to write asm? :-)
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