On Tue, Jan 18, 2011 at 07:25:24AM -0500, David Dillow wrote: > > Also when working with direct I/O from user space and/or under file-system, > > did you really see many BIOs that can be merged? I was under the impression, > > that (specifically after some time the system is active) for the most case, > > I get totally scattered SGs, whose pages can't be coalesced at all. > > I would expect that to be a common case, but there are systems out there > that this is not an issue. They typically allocate buffers early on when > they can be contiguous, and just keep reusing those.
It has become really easy to use hugetlb now, you can just mmap anonymous memory with MAP_HUGETLB and you get 2M pages. If an app is using O_DIRECT it seem worth making an attempt to use huge pages.. IIRC databases are already doing this. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
