Examples:
- Good hashing, i.e. tb_hash_func5(phys_pc, pc, flags):
TB count 715135/2684354
[...]
TB hash buckets 388775/524288 (74.15% head buckets used)
TB hash occupancy 33.04% avg chain occ. Histogram: [0,10)%|▆ █
▅▁▃▁▁|[90,100]%
TB hash avg chain 1.017 buckets. Histogram: 1|█▁▁|3
- Not-so-good hashing, i.e. tb_hash_func5(phys_pc, pc, 0):
TB count 712636/2684354
[...]
TB hash buckets 344924/524288 (65.79% head buckets used)
TB hash occupancy 31.64% avg chain occ. Histogram: [0,10)%|█ ▆
▅▁▃▁▂|[90,100]%
TB hash avg chain 1.047 buckets. Histogram: 1|█▁▁▁|4
- Bad hashing, i.e. tb_hash_func5(phys_pc, 0, 0):
TB count 702818/2684354
[...]
TB hash buckets 112741/524288 (21.50% head buckets used)
TB hash occupancy 10.15% avg chain occ. Histogram: [0,10)%|█ ▁
▁▁▁▁▁|[90,100]%
TB hash avg chain 2.107 buckets. Histogram: [1.0,10.2)|█▁▁▁▁▁▁▁▁▁|[83.8,93.0]
- Good hashing, but no auto-resize:
TB count 715634/2684354
TB hash buckets 8192/8192 (100.00% head buckets used)
TB hash occupancy 98.30% avg chain occ. Histogram:
[95.3,95.8)%|▁▁▃▄▃▄▁▇▁█|[99.5,100.0]%
TB hash avg chain 22.070 buckets. Histogram:
[15.0,16.7)|▁▂▅▄█▅▁▁▁▁|[30.3,32.0]
Suggested-by: Richard Henderson <r...@twiddle.net>
Signed-off-by: Emilio G. Cota <c...@braap.org>
---
translate-all.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/translate-all.c b/translate-all.c
index 0bf76d7..775ea79 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -1665,6 +1665,10 @@ void dump_exec_info(FILE *f, fprintf_function
cpu_fprintf)
int i, target_code_size, max_target_code_size;
int direct_jmp_count, direct_jmp2_count, cross_page;
TranslationBlock *tb;
+ struct qht_stats hst;
+ uint32_t hgram_opts;
+ size_t hgram_bins;
+ char *hgram;
target_code_size = 0;
max_target_code_size = 0;
@@ -1715,6 +1719,38 @@ void dump_exec_info(FILE *f, fprintf_function
cpu_fprintf)
direct_jmp2_count,
tcg_ctx.tb_ctx.nb_tbs ? (direct_jmp2_count * 100) /
tcg_ctx.tb_ctx.nb_tbs : 0);
+
+ qht_statistics_init(&tcg_ctx.tb_ctx.htable, &hst);
+
+ cpu_fprintf(f, "TB hash buckets %zu/%zu (%0.2f%% head buckets used)\n",
+ hst.used_head_buckets, hst.head_buckets,
+ (double)hst.used_head_buckets / hst.head_buckets * 100);
+
+ hgram_opts = QDIST_PR_BORDER | QDIST_PR_LABELS;
+ hgram_opts |= QDIST_PR_100X | QDIST_PR_PERCENT;
+ if (qdist_xmax(&hst.occupancy) - qdist_xmin(&hst.occupancy) == 1) {
+ hgram_opts |= QDIST_PR_NODECIMAL;
+ }
+ hgram = qdist_pr(&hst.occupancy, 10, hgram_opts);
+ cpu_fprintf(f, "TB hash occupancy %0.2f%% avg chain occ. Histogram:
%s\n",
+ qdist_avg(&hst.occupancy) * 100, hgram);
+ g_free(hgram);
+
+ hgram_opts = QDIST_PR_BORDER | QDIST_PR_LABELS;
+ hgram_bins = qdist_xmax(&hst.chain) - qdist_xmin(&hst.chain);
+ if (hgram_bins > 10) {
+ hgram_bins = 10;
+ } else {
+ hgram_bins = 0;
+ hgram_opts |= QDIST_PR_NODECIMAL | QDIST_PR_NOBINRANGE;
+ }
+ hgram = qdist_pr(&hst.chain, hgram_bins, hgram_opts);
+ cpu_fprintf(f, "TB hash avg chain %0.3f buckets. Histogram: %s\n",
+ qdist_avg(&hst.chain), hgram);
+ g_free(hgram);
+
+ qht_statistics_destroy(&hst);
+
cpu_fprintf(f, "\nStatistics:\n");
cpu_fprintf(f, "TB flush count %d\n", tcg_ctx.tb_ctx.tb_flush_count);
cpu_fprintf(f, "TB invalidate count %d\n",
--
2.5.0
