Re: [rfc 08/45] cpu alloc: x86 support

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Christoph Lameter wrote:
On Mon, 19 Nov 2007, H. Peter Anvin wrote:

You're making the assumption here that NUMA = large number of CPUs. This
assumption is flat-out wrong.

Well maybe. Usually one gets to NUMA because the hardware gets too big to be handleed the UMA way.

On x86-64, most two-socket systems are still NUMA, and I would expect that
most distro kernels probably compile in NUMA.  However,
burning megabytes of memory on a two-socket dual-core system when we're
talking about tens of kilobytes used would be more than a wee bit insane.

Yeah yea but the latencies are minimal making the NUMA logic too expensive for most loads ... If you put a NUMA kernel onto those then performance drops (I think someone measures 15-30%?)


How do you handle this memory, in the first place? Do you allocate the whole 2 MB for the particular CPU, or do you reclaim the upper part of the large page? (I haven't dug far enough into the source to tell.)

	-hpa
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux