- Keep a freelist of component buffer headers, defaulting
to 8 headers per component (tunable with the CCDNBUF
kernel compile option).
- When allocating a component buffer, try to pull a header
off the freelist first, falling back on MALLOC() if the
freelist is empty. Use MALLOC() rather than malloc(),
because it will attempt to short-cut the allocation before
actually making a full-blown malloc() call.
- Keep statistics on how many component buffer headers have
been allocated and how many of those allocations have
resulted in freelist misses.
With these changes, I observed measurable decreases in system and
wall clock time on operations on an 8G ccd, as well as a measurable
drop in the time spent in ccdbuffer() (measured with kernel profiling).
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