On 10/21/2008 04:02 PM, Ben Scott wrote:
The original reason for the sticky bit is because some Unix commands are so frequently used and small that keeping them in memory significantly improves performance, especially in a multi-user system.According to everything I've ever read, Linux ignores the sticky bit on executables. Wikipedia has a good summary:http://en.wikipedia.org/wiki/Sticky_bit
I believe from my previous research on Linux virtual memory that commands will remain in virtual memory long enough to where the sticky bit is not needed. First of all the text (instructions and read-only data) are never copied to swap as they are mapped into VM from their physical location. older Unix systems used to copy the program to swap, then a newer technique was to load it into memory and mark it as dirty. Putting this in terms of the shell and Perl, because the shell (bash) is constantly being used, it is probably always resident in physical memory and never paged out. Perl, on the other hand may need to be loaded, causing a Perl script to appear to be slower than a shell script. Additionally, Perl compiles the script first. But, comparing a Perl script to a shell script is somewhat comparing apples and PCs. Perl incorporates the features of SED and AWK. So, if you were to create a shell script that used these features, you might find that Perl willl out perform BASH. Another was that you can look at performance is to use a C shell script on a system where the C Shell is not used as a login shell, so it is generally not resident.
-- Jerry Feldman <[EMAIL PROTECTED]> Boston Linux and Unix PGP key id: 537C5846 PGP Key fingerprint: 3D1B 8377 A3C0 A5F2 ECBB CA3B 4607 4319 537C 5846
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