On Wed, 04 Nov 2009 18:32:41 +0100 Tim Blechmann <tim@xxxxxxxxxx> wrote: > >> well, if i understand the rt howto correctly, _no_ disc access is > >> allowed, neither from rt nor from non-rt threads, since it may produce > >> page faults, which introduce latencies ... > > > > I would be supprised if the rt howto states that page-faults in non-rt > > threads is a critical problem - that would not significantly impact RT > > performance - atelast not the worst case - it will (as every other system > > load) impact the average case. so having a non-rt thread reading disk-files > > to a buffer and a rt-thread processing this buffer should be perfectly fine. > > that is what i thought for years ... but according to [1] a page fault > in an rt process freezes the entire process with both rt and non-rt > threads until the page fault is handled ... > No, we need to get that fixed in the wiki. It may have been the case that the entire process was frozen while a fault was being handled, but I don't believe that is the case now. If you're in a thread on core0 and a sibling thread on core1 faults, you shouldn't be impacted unless you're trying to reference the same memory. Clark
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