Intel KMS vs. UMS With Ubuntu 10.04

“Last week we published benchmarks looking at the ATI Radeon KMS
vs. UMS performance and found the user-space mode-setting support
with the ATI driver (that is also limited to using DRI1 with these
older code-paths) to perform significantly faster than the newer
kernel mode-setting routes in most instances. To see how the
performance difference is on the Intel side between the kernel
mode-setting and user-space mode-setting implementations we ran a
set of benchmarks on this side as well using Ubuntu 10.04.

“Intel’s Linux graphics driver was the first open-source driver
to implement support for an in-kernel memory manager (in the form
of the Graphics Execution Manager) followed by kernel-based
mode-setting support. The GEM memory work landed with the Linux
2.6.28 kernel back in 2008 followed by the Intel KMS support and
the kernel mode-setting infrastructure came with the Linux 2.6.29
kernel in early 2009. The mainline Intel KMS support is barely a
year old, but support for the older user-space mode-setting code
paths were already dropped. The UMS support was dropped with the
xf86-video-intel 2.10 driver delivered back in January to reduce
the driver’s code-base, close many open bugs surrounding user-space
mode-setting, and since KMS is in fact the future. Intel is right
now in the process of preparing the xf86-video-intel 2.11 driver
that is its second KMS-only X.Org driver release.”

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