Commit f9d5c95f authored by Simon Marlow's avatar Simon Marlow

On x86, use thread-local storage instead of stealing a reg for gct

Benchmarks show that using TLS instead of stealing a register is
better by a few percent on x86, due to the lack of registers.

This only affects -threaded; without -threaded we're (now) using
static storage for the GC data.
parent ed45b268
......@@ -209,10 +209,15 @@ extern gc_thread **gc_threads;
#define SET_GCT(to) gct = (to)
#if defined(sparc_HOST_ARCH)
#if defined(sparc_HOST_ARCH) || defined(i386_HOST_ARCH)
// Don't use REG_base or R1 for gct on SPARC because they're getting clobbered
// by something else. Not sure what yet. -- BL 2009/01/03
// Using __thread is better than stealing a register on x86, because
// we have too few registers available. In my tests it was worth
// about 5% in GC performance, but of course that might change as gcc
// improves. -- SDM 2009/04/03
extern __thread gc_thread* gct;
#define DECLARE_GCT __thread gc_thread* gct;
......
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