[ale] redhat 9 ramdrive performance problem

[Armsby John-G16665]

Sorry for the delay.  Actually I am talking about a real ramdisk..

http://www.vanemery.com/Linux/Ramdisk/ramdisk.html

I will take another look at top and see if I can deduce anything.....  My cgi applications simply reads greps several 50+ meg files and spews out html tables.

John


-----Original Message-----
From: ale-bounces at ale.org [mailto:ale-bounces at ale.org] On Behalf Of Danny Cox
Sent: Thursday, April 29, 2004 5:13 PM
To: Atlanta Linux Enthusiasts
Subject: Re: [ale] redhat 9 ramdrive performance problem


John,

On Thu, 2004-04-29 at 08:29, Armsby John-G16665 wrote:
> I have successfully set up a ramdrive with 500 meg of space, 
> initialized it, and placed the files I need to regularly access.  I 
> have changed the CGI code to look to that directory (/mnt/ramdrive) to 
> access the files.  I am dismayed to find that the performance is 
> actually less than simply using normal disk access.
>  
> Previously I have set up an identical configuration on a Dell GX 270, 
> 1 Gig of ram, and noticed a 2X increase in performance.  I measure 
> performance by having the cgi script simply calculate the number of 
> seconds it is running.  Both machines are running redhat 9, both 
> machines are running the identical compiled cgi script.  Index files 
> are identical.

	Are you perhaps swapping?  See top(1) or even vmstat(8) and look at the si and so columns (swap-ins/swap-outs).

	I have 512 MB on my desktop, and I can sometimes swap when using Gnome/Evolution/FireFox/Gnumeric.  I know that's comparing my setup to a server, but still.

	Also, what do the CGI scripts do?  Mostly read the ramdisk files? 
Write 'em?  Read AND write (database)?

	While it's doing it's thing, run top, and see where the CPU time is
going: user, system, nice, or idle.  That might give you a hint.

	What FS did you build on the ramdisk?

	Okay, I'm beginning to ramble.

-- 
kernel, n.: A part of an operating system that preserves the medieval traditions of sorcery and black art.

Danny

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