** Changed in: linux (Ubuntu Zesty)
Status: In Progress => Fix Committed
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https://bugs.launchpad.net/bugs/1711096
Title:
dma-buf: performance issue when looking up the fence status
Status in linux package in Ubuntu:
Triaged
Status in linux source package in Zesty:
Fix Committed
Bug description:
SRU Request:
[Impact]
When a timeout of zero is specified, the caller is only interested in
the fence status.
In the current implementation, dma_fence_default_wait will always call
schedule_timeout() at least once for an unsignaled fence. This adds a
significant overhead to a fence status query.
Avoid this overhead by returning early if a zero timeout is specified.
[Test Case]
1) Install the new kernel
2) Download amdgpu-pro-17.30-465504.tar.xz from http://support.amd.com
/en-us/kb-articles/Pages/AMDGPU-PRO-Driver-for-Linux-Release-
Notes.aspx, and follow the install guide to install the driver on
Ubuntu 16.04.3
3) Install Unigine Heaven to get performance score
4) Rmeove DKMS, remove this patch
http://git.amd.com:8080/gitweb?p=brahma/ec/linux.git;a=commit;h=8586edda6677b90f3971919f3c6babbbec4b5b8c
from DKMS source code, and install DKMS
5) re-run the benchmark, and check if there's any obvious performance
drop.
[Regression Potential]
Low, the patch is very small, and it is already available upstream.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=03c0c5f6641533f5fc14bf4e76d2304197402552
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