Re: [Gnu-arch-users] Re: [PATCH] arch speedups on big trees

[Dustin Sallings]

On Jan 12, 2004, at 6:25, David Allouche wrote:

> What this does is just mallocing and touching memory until the kernel
> out-of-memory killer nukes the program.
>
> That flushes all kernel caches and buffers as well as possible. Only
> problem is _if_ you have an oversized swap, it will be slow. Anyway
> having an oversized swap is a bad thing, because real-life programs
> sometimes go berserk this way, and with too big a swap they can make
> your system unusable for ages before the OOM killer comes.

	I wrote a similar one to figure to clean out the caches (which greatly 
helped with performance in a few cases), and try to figure out how 
large of a block can be allocated on a system.  It does this by 
grabbing larger blocks until ENOMEM, and then shrinking it by one until 
I don't get an ENOMEM.

	The problem I had the last time I ran it wasn't an oversized swap, but 
a dynamic swap (swap was dynamically growing with demands).  That was a 
bit unfortunate.

--
Dustin Sallings