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what's needed is a application barrier() call

what's needed is a application barrier() call

Posted Sep 10, 2009 7:35 UTC (Thu) by njs (guest, #40338)
In reply to: what's needed is a application barrier() call by dlang
Parent article: POSIX v. reality: A position on O_PONIES

But now you're synchronizing all writes by all processes everywhere on the disk, not just the two blocks that actually got written to in this one file somewhere. If apps used that sort of barrier() too often then I think you'd end up with disk throughput that looks like you mounted with -o sync -- very little reordering would ever be allowed.

I guess this is complicated by the question of when dirty blocks get flushed, and in how large batches; maybe it's solvable. But I don't think memory is the main concern, at least.


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what's needed is a application barrier() call

Posted Sep 10, 2009 7:48 UTC (Thu) by dlang (subscriber, #313) [Link]

you are absolutely correct, that's why I say it's only a 90% solution, but it may be something that gives you most of the benefit for a fraction of the effort.


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