Re: [ossig] Zope faster than Apache?

[Tze-Meng Tan <tmtan@opensos.net>]

How fast an overall program is depends more on how well the programmer 
wrote the code and to some extent how good the compiler programmer is:

typically operations which happen thousands and millions of times 
during the execution of a program will benefit from 
optimisation...which means good code design and implementation, getting 
a good compiler (pretty much language independent) and maybe even hand 
coding assembly language for really performance critical stuff.

Once these critical modules are optimised all other code which may only 
execute a few times doesn't need to be optimised, you can but the 
effort will not be worth it.....law of diminishing returns, you can 
spend days optimising but will little to show for it

The most important excerpt for me is this "my server guy said Apache 
was designed for correctness and not for speed". "Correctness" 
indicates to me that the code does a lot of sanity checking....thats 
overhead which leads to lower performance but ultimately safer and more 
secure code which is an acceptable trade off.

Sometimes language rules can affect performance. Pascal and relatives 
(ADA, Modula etc) for example do bounds checking for arrays, so if 
program inputs cause an array index to go beyond bounds you get an 
index out of bounds run time error. This code is overhead and does slow 
overall performance. In Turbo Pascal you could turn this code off and 
all hell will break loose (ie buffer overflows and relatives) if you 
didn't write your own sanity checking code. C however does not do range 
checking so its up to the programmer to do the sanity checking.....if 
something is written for speed, then sanity checking isn't so thorough, 
or the programmer is too lazy to check for all possible inputs.... you 
get security holes.

Me? I rather have less performance and more correctness :)


On Wednesday, Jun 25, 2003, at 13:20 Asia/Kuala_Lumpur, Mukhsein Johari 
wrote:

> Are programs written totally in C necessarily faster than programs 
> written in Python plus a few C modules? This is something I've been 
> thinking about and here is some anecdotal evidence that it's not 
> always so. Of course, it's possible this is an Apache config related 
> issue that Bruce forgot but it's also possible that it's not.
>
>
> ------------------
> http://www.artima.com/intv/prodperf.html
> Excerpt from Bruce interview:
>
> Take Zope, for example. Zope is the enterprise application server I 
> use for my website. Zope is virtually all Python, but includes some C 
> code, because they profiled and optimized Zope so it would run faster. 
> When Zope was put on my machine, I discovered it was noticeably faster 
> than Apache had been. That seemed surprising to me, but my server guy 
> said Apache was designed for correctness and not for speed, so it 
> wasn't that surprising to him. Because Apache was written in C, I 
> figured it ought to be faster. But it turned out Zope was faster.
> ------------------
>
>
> A number of the standard modules are in fact written in C for speed of 
> execution. A number of scientific python modules (NumArray/numpy/scipy 
> related stuff) are also written in C. Python allows you to select 
> which modules to optimize in C and which to leave as python using 
> profilers. What this effectively means is that you can develop faster 
> with python _and_ have a faster executing program (once C-optimized, 
> if needed) for delivery. I can have my cake and eat it too. I rather 
> like that...
>
> Regards,
> Mukhsein Johari
>
> --
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