Re: AIX perfomance

2003-09-17 Thread William McCabe
Hi Ged,

On 9/12/03 at 4:12 PM, [EMAIL PROTECTED] (Ged Haywood) wrote:

 
 Roughly what hardware setups do you generally work with, and what
 differences are notable between Linux and AIX when running mod_perl
 servers?  (If that's not too long a piece of string to measure:).
 Are there situations where you'd prefer one or the other, if so why?

Sorry for the slow response; I've been out of town. Most of my mod_perl/AIX
systems are used to generate organizational performance reports, basically
data-mart type stuff, which is very DBI (DB2) and computationally-intensive, and
also often invlove running COBOL binaries which have been ported from OS/390 and
run via RPC::XML. If the need to run COBOL is absent from a project, then I
usually deploy on Lintel, since procurement is so much easier. I never rely on
OS ditributions of perl, apache, or mod_perl so my working enviroment is always
identical. As I mentioned earlier, Rafael should not be experience slowness on
AIX unless he's comparing dated RS/6000 hardware with new Intel. Scalability,
especially with big SMP iron, still favors the RS/6000 though at a colossal
cost.

Bill


Re: AIX perfomance

2003-09-12 Thread William McCabe
On 9/12/03 at 2:07 PM, [EMAIL PROTECTED] (Rafael Garcia-Suarez)
wrote:

 I've a mod_perl application we've developed on Linux and that
 we're porting on AIX (4.3.3 and 5.2.0). The AIX boxes are
 supposed to be more powerful than their Linux equivalents,
 however the application is strangely slow on AIX -- the httpd
 configuration being similar. And that's mod_perl 1.28.
 
 So I'm asking for the common wisdom about performance
 issues on AIX. Currently the perl I use is built with
 gcc and default settings. Should I set -Dusemymalloc=y ?
 Should I use the xlC or vac compilers ? Should I port
 everything to mod_perl 2 ? (which I haven't succeeded
 to build on AIX 4 by now BTW -- but I'm working on it.)

I've built many mod_perl applications on linux and moved them to AIX 4.3.3 with
no detriment at all. What do you mean by strangely slow?

BIll


Re: AIX perfomance

2003-09-12 Thread William McCabe
On 9/12/03 at 2:54 PM, [EMAIL PROTECTED] (Ged Haywood) wrote:

  Benchmarking simple CPU-intensive perl scripts shows that they
  tend to be consistently slower in user time on AIX.
 
 Assuming that the boxes aren't otherwise heavily loaded, I wonder
 about the options used to compile your Perl.  For x86 architecture,
 things like -mcpu=i386 will make a binary that you could run on a
 steam engine but it won't be able to take advantage of the richer
 instruction set on newer processors.  I don't have a great deal of
 experience with other modern processors, but from the gcc 3.2.3
 documentation:
 
 GCC defaults to `-maix32'
 
 and there's a '-maix64' that may be worth a look, along with the rest
 of the section ('info gcc' if you have it).
 
 Optimisation may also be an issue, but use caution.  Many packages
 (e.g. the Linux kernel sources :) warn against anything more than
 using -O2 with gcc for example.

I think it's pretty useless to speculate as to causes until he clarifies what
strangely slow means and what AIX and linux hardware he's comparing. I've got
a lot of experience with mod_perl on both linux and AIX and can state
categorically that there are no typical conditions which would cause AIX run
strangely slowly compared to linux on comparable hardware.

Bill