[patch 00/12] Immediate Values

Mathieu Desnoyers
2009-09-24T14:42:47Z

Hi Ingo,

Here is an updated version of the immediate values, applying to current tip.

[impact: data-cache optimization]

The main benefit of this infrastructure is to encode read-often variables into
the instruction stream. It can benefit to tracepoints by replacing the memory
load by an immediate value instruction. There is still room for improvement
through: an effort to provide static jump patching is ongoing, involving the
kernel and gcc communities.

Even then, the immediate values have their niche: when a value (rather than a
branch selection) is read often on fast-paths, the immediate value
infrastructure can encode these in the instruction stream without any d-cache
cost.

Two sample users are provided: prof_on from the scheduler code and tracepoints.
Feel free to merge/drop any of these.

Thanks,

Mathieu