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On 10/06/10 18:43, Paul H. Hargrove wrote:
> When the file is on a real (not tmpfs or other ramdisk) I am 95% certain
> that this is an artifact of the Linux swapper/pager behavior which is
> thinking it is being smart by "swapping ahead". Even when
Chris,
I think that "reclaiming pages from the page cache" is the PROBLEM,
not the solution. If I understand you correctly a lower value of
"swappiness" means that the ANONYMOUS pages of an application's stack
and heap are less likely to be subject to swap I/O. However, the
concern here is
Sylvain Jeaugey wrote:
On Thu, 10 Jun 2010, Paul H. Hargrove wrote:
[snip]
As for why mmap is slower. When the file is on a real (not tmpfs or
other ramdisk) I am 95% certain that this is an artifact of the Linux
swapper/pager behavior which is thinking it is being smart by
"swapping ahea
On Jun 11, 2010, at 5:43 AM, Paul H. Hargrove wrote:
> > Interesting. Do you think this behavior of the linux kernel would
> > change if the file was unlink()ed after attach ?
>
> As Jeff pointed out, the file IS unlinked by Open MPI, presumably to
> ensure it is not left behind in case of abnorm
On Fri, 11 Jun 2010, Jeff Squyres wrote:
On Jun 11, 2010, at 5:43 AM, Paul H. Hargrove wrote:
Interesting. Do you think this behavior of the linux kernel would
change if the file was unlink()ed after attach ?
After a little talk with kernel guys, it seems that unlinking wouldn't
change anythi
Just FYI: We fixed some Solaris issues in the hwloc paffinity the other day; it
appears to be working properly on all platforms how. We'll let it soak a
little longer, but I think we're looking good for the first step of removing
all other paffinity components and just leaving hwloc and test.
On Jun 11, 2010, at 5:10 AM, Jeff Squyres wrote:
> On Jun 11, 2010, at 5:43 AM, Paul H. Hargrove wrote:
>
>>> Interesting. Do you think this behavior of the linux kernel would
>>> change if the file was unlink()ed after attach ?
>>
>> As Jeff pointed out, the file IS unlinked by Open MPI, presum
On Jun 11, 2010, at 12:53 PM, Barrett, Brian W wrote:
> The idea was one large memory segment for all processes and it wasn't
> unlinked after complete attach so that we could have spawned procs also use
> shmem (which never worked, of course). So I think we could unlink during
> init at this
