Re: paging behavior in Linux

[Manfred Spraul]

> 
> When I run my program on a readhat linux machine, I dont get results as 
> expected, work thread seems to be stuck when prefetch thread is waiting on 
> a page fault
>
That's a known problem:

The paging io for a process is controlled with a per-process semaphore.
The semaphore is held while waiting for the actual io. Thus the paging
in multi threaded applications is single threaded.
Probably your prefetch thread is waiting for disk io, and the worker
thread causes a minor pagefault --> worker thread sleeps until the disk
io is completed.

--
	Manfred