msm: secure_buffer: Limit continuous time spent in hypervisor
hyp_assign_table() is a costly operation during which nonsecure interrupts
are disabled. Split this operation into multiple parts for better
real-time behavior.
Splitting is done by the following criteria:
maximum number of physically contiguous memory regions
maximum total memory size.
Here is a chart showing the average performance of hyp_assign_table() with
N physically contiguous chunks each with size X.
#chunks chunk_size(pages) total_memory(pages) time(ms)
2 1 2 3.354
2 4 8 12.979
2 512 1024 4.349
8 1 8 4.714
8 4 32 26.781
8 512 4096 8.724
32 1 32 17.093
32 4 128 50.700
32 512 16384 26.717
128 1 128 71.076
128 4 512 126.305
Based on the above, select a maximum of 32 chunks or 512 total pages
as the limits.
Change-Id: I530cfdce76c8a2c38f60d6118647eaefd269e693
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
1 file changed