On 11/21/21 10:36 PM, Theo de Raadt wrote:
Scott Cheloha <[email protected]> wrote:
The point of diminishing returns on my machine is 128K.
...
So, is 128K ok? Any objections?
Many of us have forgotten that our testing machines are at the fast end
of the curve.
I recommend 64K. I suspect that is still the sweet spot for userland.
Above 64K, I think you are hogging the layers of dcache against other
processes. Testing this program in isolation is a micro-benchmark.
On my slow, small machines transfers > 64K definitely run slower
than -exactly- 64K. Any transfer > MAXPHYS needs 2 i/o ops.
Anything less wastes time in system calls.
My machines are 1.5-2GHz 8GB 2-4 core low end Intel CPUs
