Getting/Forcing Greater than 4KB Buffer Allocations
Chuck Swiger
cswiger at mac.com
Wed Jul 18 00:14:37 UTC 2007
On Jul 17, 2007, at 4:54 PM, David Christensen wrote:
> I'm investigating a problem with my bce driver which occurs when I ask
> for a jumbo mbuf cluster (through m_cljget()). When I map the
> memory for DMA I
> normally get 3 memory segments (4KB + 4KB + 1KB) on my system, but
> on another
> user's system he's seeing 2 memory segments (8KB + 1KB). Is there a
> configurationoption that allows this or some other tuning variable
> involved? The
> system is a Xeon dual-core processor and has 8GB of RAM, running an
> AMD64 version of
> the kernel.
Hi, Dave--
Is "sysctl hw.pagesize" different on the two systems? It sure looks
like the first machine is using a 4KB pagesize, whereas the second
machine is using an 8KB pagesize...
--
-Chuck
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