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From: Julian S. <js...@ac...> - 2011-11-08 21:27:05
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> On Tuesday, November 08, 2011, Philippe Waroquiers wrote: > > Florian tried a fence on s390x, and I tried a fence on amd64. > None of these solved the problem reliably. Sure. I am not saying that I think a fence will solve the problem reliably. I do think that not having fences will make it impossible to solve it reliably though. > So, it looks like at least for this test, the safest (or mandatory?) > changes would be: * have a clean solution for the delay500ms (because on > small overloaded computers, delay500ms might not be enough) > * have fence instructions > * have fair scheduling (otherwise, on big computers with enough idle > CPUs, the unfairness might cause a non termination as only one thread ever > runs). I agree. So, where did we get to with the fair scheduling? I can't remember the final outcome w.r.t. performance loss (if any). Perhaps a conservative approach is to add fair scheduling, but have it disabled by default and enabled with a command line flag, which we can add to the relevant .vgtest files. J |