diff options
| author | Richard Henderson <rth@twiddle.net> | 2015-09-26 09:23:42 -0700 |
|---|---|---|
| committer | Richard Henderson <rth@twiddle.net> | 2015-10-07 20:40:00 +1100 |
| commit | 126d89e8cdfa3be15d51f76906eaccbcd0023f98 (patch) | |
| tree | d188780cff94a0c3f48f277220c4707c39f3cf0d | |
| parent | b125f9dc7bd68cd4c57189db4da83b0620b28a72 (diff) | |
tcg: Adjust CODE_GEN_AVG_BLOCK_SIZE
At present, the "average" guestimate of TB size is way too small, leading
to many unused entries in the pre-allocated TB array. For a guest with 1GB
ram, we're currently allocating 256MB for the array.
Survey arm, alpha, aarch64, ppc, sparc, i686, x86_64 guests running on
x86_64 and ppc64 hosts and select a new average. The size of the array
drops to 81MB with no more flushing than before.
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
| -rw-r--r-- | include/exec/exec-all.h | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h index 71c9d85278..a63fd6015e 100644 --- a/include/exec/exec-all.h +++ b/include/exec/exec-all.h @@ -161,13 +161,14 @@ static inline void tlb_flush_by_mmuidx(CPUState *cpu, ...) #define CODE_GEN_PHYS_HASH_BITS 15 #define CODE_GEN_PHYS_HASH_SIZE (1 << CODE_GEN_PHYS_HASH_BITS) -/* estimated block size for TB allocation */ -/* XXX: use a per code average code fragment size and modulate it - according to the host CPU */ +/* Estimated block size for TB allocation. */ +/* ??? The following is based on a 2015 survey of x86_64 host output. + Better would seem to be some sort of dynamically sized TB array, + adapting to the block sizes actually being produced. */ #if defined(CONFIG_SOFTMMU) -#define CODE_GEN_AVG_BLOCK_SIZE 128 +#define CODE_GEN_AVG_BLOCK_SIZE 400 #else -#define CODE_GEN_AVG_BLOCK_SIZE 64 +#define CODE_GEN_AVG_BLOCK_SIZE 150 #endif #if defined(__arm__) || defined(_ARCH_PPC) \ |