Unix performance tips
Dec. 3rd, 2003 10:47 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
sobriqueJust been reading a little article about the linux kernel. A little known fact, is that kernels of a higher version than 1.3.4 have an application optimisation routine.
Basically, what it does is pre-exec's a program, past conditional branches effectively caching possible program states. So basically if you have a wait state for whatever reason (eg. waiting for user input) the pre-exec runs down it's execution paths, for several of the more probable program states.
It's not enabled by default, because there are a few potential problems - specifically with 'big' relational databases like oracle, DB2 etc. It won't _kill_ them, but it will slow them down somewhat.
This method can, with particular application types, give a 20-40% increase in 'responsiveness' - it's especially apparant with games, or other programs that require extensive user input.
It's actually quite easy to enable too. It can be set in 'user mode' or 'system mode'. The operation to enable is the same - just add 'exec true' to the appropriate profile. Obviously if you put it in the system profile (/etc/system) it'll cause all the various daemons to run in exec mode, whereas if you just put in in a user profile, it'll only affect user owned processes.
If you're running Oracle, you may notice a slowness, in which case it's probably worth disabling again (exec false, or just delete the line)
Basically, what it does is pre-exec's a program, past conditional branches effectively caching possible program states. So basically if you have a wait state for whatever reason (eg. waiting for user input) the pre-exec runs down it's execution paths, for several of the more probable program states.
It's not enabled by default, because there are a few potential problems - specifically with 'big' relational databases like oracle, DB2 etc. It won't _kill_ them, but it will slow them down somewhat.
This method can, with particular application types, give a 20-40% increase in 'responsiveness' - it's especially apparant with games, or other programs that require extensive user input.
It's actually quite easy to enable too. It can be set in 'user mode' or 'system mode'. The operation to enable is the same - just add 'exec true' to the appropriate profile. Obviously if you put it in the system profile (/etc/system) it'll cause all the various daemons to run in exec mode, whereas if you just put in in a user profile, it'll only affect user owned processes.
If you're running Oracle, you may notice a slowness, in which case it's probably worth disabling again (exec false, or just delete the line)
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Date: 2003-12-05 08:27 am (UTC)