Messages in this thread | | | Date | 2 Mar 2001 13:43:03 CST | From | Neelam Saboo <> | Subject | [Re: paging behavior in Linux] |
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hi,
After I installed a newer version of Kernel (2.4.2) and enable DMA option in hardware configuration, the behavior changes. I can see performance improvements when another thread is used. Also, i can see timing overlaps between two threads. i.e. when one thread is blocked on a page fault, other thread keeps working. Now, how can this behavior be explained , given the earlier argument. Is it that, a newer version of kernel has fixed the problem of the semaphore ?
thanks neelam
> 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
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