AIX perfomance
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.)
Re: AIX perfomance
Hi there, On Fri, 12 Sep 2003, Rafael Garcia-Suarez wrote: > 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 You don't give much to go on. Are they really more powerful? What does 'powerful' mean anyway? What discs do you have and what interfaces do they use, how much memory, what processors, speeds, how many mod_perl processes, how big are they, are you getting into swap, etc...? Have you benchmarked some simple things on the boxes? > So I'm asking for the common wisdom about performance issues on AIX. I don't know anything worth writing about AIX but I'd look a little deeper into what you're doing before you start blaming the OS. > 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 ? To all those questions at this stage, my answer would be 'I doubt it'. Find out about your systems first. There are lots of tools to help you do that. Start by checking the relevant sections of the Guide for more information about performance and benchmarking. (Or look at the little disc activity light. :) 73, Ged.
Re: AIX perfomance
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
Ged Haywood wrote: > Hi there, > > On Fri, 12 Sep 2003, Rafael Garcia-Suarez wrote: > > > 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 > > You don't give much to go on. Are they really more powerful? > > What does 'powerful' mean anyway? What discs do you have and what > interfaces do they use, how much memory, what processors, speeds, how > many mod_perl processes, how big are they, are you getting into swap, > etc...? Well, it's difficult to compare very different hardware, but basically the AIX boxen have SCSI discs, more memory, etc. and they're a lot more expensive ;-) > Have you benchmarked some simple things on the boxes? Benchmarking simple CPU-intensive perl scripts shows that they tend to be consistently slower in user time on AIX. Moreover if I survey CPU/memory usage on Linux and AIX (resp. with top and vmstat / w) I see that the application doesn't swap memory and that the load averages remains < 0.10. > > So I'm asking for the common wisdom about performance issues on AIX. > > I don't know anything worth writing about AIX but I'd look a little > deeper into what you're doing before you start blaming the OS. > > > 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 ? > > To all those questions at this stage, my answer would be 'I doubt it'. > Find out about your systems first. There are lots of tools to help > you do that. Start by checking the relevant sections of the Guide for > more information about performance and benchmarking. (Or look at the > little disc activity light. :) Thanks, I'll dig deeper.
Re: AIX perfomance
Hi there,
On Fri, 12 Sep 2003, Rafael Garcia-Suarez 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.
73,
Ged.
Re: AIX perfomance
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
Re: AIX perfomance
Hi there, On Fri, 12 Sep 2003, William McCabe wrote: > 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. That's useful information, thanks Bill. We don't see much about AIX here but it seems to me that it's been becoming more common recently. 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? 73, Ged.
Re: AIX perfomance
On Fri, 2003-09-12 at 09:35, Rafael Garcia-Suarez wrote: > Benchmarking simple CPU-intensive perl scripts shows that they > tend to be consistently slower in user time on AIX. Are these mod_perl scripts or just Perl? If you benchmark some simple Perl scripts that don't run under mod_perl and they show the same trend, then you can eliminate mod_perl as a possible source of the problem. You should also verify that your versions of Perl, apache, and mod_perl are exactly the same on both systems. - Perrin
Re: AIX perfomance
On Fri, Sep 12, 2003 at 04:12:00PM +0100, Ged Haywood wrote: > Hi there, > > On Fri, 12 Sep 2003, William McCabe wrote: > > > 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. > > That's useful information, thanks Bill. We don't see much about AIX > here but it seems to me that it's been becoming more common recently. > AIX will of course have an massive growth in popularity now that SCO has withdrwan IBMs un*x licence. ;*> Paddy
Re: AIX perfomance
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
