[Qemu-devel] [PATCH v7 02/10] accel: collecting JIT statistics

[vandersonmr <vandersonmr2@gmail.com>]

If a TB has a TBS (TBStatistics) with the TB_JIT_STATS
enabled then we collect statistics of its translation
processes and code translation.

Collecting the number of host instructions seems to be
not simple as it would imply in having to modify several
target source files. So, for now, we are only collecting
the size of the host gen code.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Vanderson M. do Rosario <vandersonmr2@gmail.com>
---
 accel/tcg/translate-all.c | 15 ++++++++++++++-
 accel/tcg/translator.c    |  4 ++++
 include/exec/tb-stats.h   | 15 +++++++++++++++
 tcg/tcg.c                 | 23 +++++++++++++++++++++++
 tcg/tcg.h                 |  2 ++
 5 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index e72aeba682..fb2fe0fa1f 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -1705,6 +1705,7 @@ static TBStatistics *tb_get_stats(tb_page_addr_t phys_pc, target_ulong pc,
          * then just make the new TB point to the older TBStatistic
          */
         g_free(new_stats);
+        ((TBStatistics *) existing_stats)->tb = current_tb;
         return existing_stats;
     } else {
         return new_stats;
@@ -1785,13 +1786,18 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
      */
     if (tb_stats_collection_enabled()) {
         tb->tb_stats = tb_get_stats(phys_pc, pc, cs_base, flags, tb);
+        uint32_t flag = get_default_tbstats_flag();
 
         if (qemu_log_in_addr_range(tb->pc)) {
-            uint32_t flag = get_default_tbstats_flag();
             if (flag & TB_EXEC_STATS) {
                 tb->tb_stats->stats_enabled |= TB_EXEC_STATS;
             }
         }
+
+        if (flag & TB_JIT_STATS) {
+            tb->tb_stats->stats_enabled |= TB_JIT_STATS;
+            atomic_inc(&tb->tb_stats->translations.total);
+        }
     } else {
         tb->tb_stats = NULL;
     }
@@ -1869,6 +1875,10 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
     atomic_set(&prof->search_out_len, prof->search_out_len + search_size);
 #endif
 
+    if (tb_stats_enabled(tb, TB_JIT_STATS)) {
+        atomic_add(&tb->tb_stats->code.out_len, gen_code_size);
+    }
+
 #ifdef DEBUG_DISAS
     if (qemu_loglevel_mask(CPU_LOG_TB_OUT_ASM) &&
         qemu_log_in_addr_range(tb->pc)) {
@@ -1926,6 +1936,9 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
     phys_page2 = -1;
     if ((pc & TARGET_PAGE_MASK) != virt_page2) {
         phys_page2 = get_page_addr_code(env, virt_page2);
+        if (tb_stats_enabled(tb, TB_JIT_STATS)) {
+            atomic_inc(&tb->tb_stats->translations.spanning);
+        }
     }
     /*
      * No explicit memory barrier is required -- tb_link_page() makes the
diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
index ec6bd829a0..9b2e248b09 100644
--- a/accel/tcg/translator.c
+++ b/accel/tcg/translator.c
@@ -116,6 +116,10 @@ void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
     db->tb->size = db->pc_next - db->pc_first;
     db->tb->icount = db->num_insns;
 
+    if (tb_stats_enabled(tb, TB_JIT_STATS)) {
+        atomic_add(&db->tb->tb_stats->code.num_guest_inst, db->num_insns);
+    }
+
 #ifdef DEBUG_DISAS
     if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM)
         && qemu_log_in_addr_range(db->pc_first)) {
diff --git a/include/exec/tb-stats.h b/include/exec/tb-stats.h
index c4a8715400..b68edd5d24 100644
--- a/include/exec/tb-stats.h
+++ b/include/exec/tb-stats.h
@@ -58,6 +58,20 @@ struct TBStatistics {
         unsigned long atomic;
     } executions;
 
+    struct {
+        unsigned num_guest_inst;
+        unsigned num_tcg_ops;
+        unsigned num_tcg_ops_opt;
+        unsigned spills;
+        unsigned out_len;
+    } code;
+
+    struct {
+        unsigned long total;
+        unsigned long uncached;
+        unsigned long spanning;
+    } translations;
+
     /* current TB linked to this TBStatistics */
     TranslationBlock *tb;
 };
@@ -71,6 +85,7 @@ enum TBStatsStatus { TB_STATS_RUNNING, TB_STATS_PAUSED, TB_STATS_STOPPED };
 
 #define TB_NOTHING    (1 << 0)
 #define TB_EXEC_STATS (1 << 1)
+#define TB_JIT_STATS  (1 << 2)
 
 extern int tcg_collect_tb_stats;
 extern uint32_t default_tbstats_flag;
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 0458eaec57..ae3e7a2217 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -3125,6 +3125,11 @@ static void temp_sync(TCGContext *s, TCGTemp *ts, TCGRegSet allocated_regs,
         case TEMP_VAL_REG:
             tcg_out_st(s, ts->type, ts->reg,
                        ts->mem_base->reg, ts->mem_offset);
+
+            /* Count number of spills */
+            if (tb_stats_enabled(s->current_tb, TB_JIT_STATS)) {
+                atomic_inc(&s->current_tb->tb_stats->code.spills);
+            }
             break;
 
         case TEMP_VAL_MEM:
@@ -3996,6 +4001,8 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
     int i, num_insns;
     TCGOp *op;
 
+    s->current_tb = tb;
+
 #ifdef CONFIG_PROFILER
     {
         int n = 0;
@@ -4027,6 +4034,14 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
     }
 #endif
 
+    if (tb_stats_enabled(tb, TB_JIT_STATS)) {
+        int n = 0;
+        QTAILQ_FOREACH(op, &s->ops, link) {
+            n++;
+        }
+        atomic_add(&tb->tb_stats->code.num_tcg_ops, n);
+    }
+
 #ifdef CONFIG_DEBUG_TCG
     /* Ensure all labels referenced have been emitted.  */
     {
@@ -4093,6 +4108,14 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
     }
 #endif
 
+    if (tb_stats_enabled(tb, TB_JIT_STATS)) {
+        int n = 0;
+        QTAILQ_FOREACH(op, &s->ops, link) {
+            n++;
+        }
+        atomic_add(&tb->tb_stats->code.num_tcg_ops_opt, n);
+    }
+
     tcg_reg_alloc_start(s);
 
     s->code_buf = tb->tc.ptr;
diff --git a/tcg/tcg.h b/tcg/tcg.h
index 529acb2ed8..b4601162f8 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -740,6 +740,8 @@ struct TCGContext {
 
     uint16_t gen_insn_end_off[TCG_MAX_INSNS];
     target_ulong gen_insn_data[TCG_MAX_INSNS][TARGET_INSN_START_WORDS];
+
+    TranslationBlock *current_tb;
 };
 
 extern TCGContext tcg_init_ctx;
-- 
2.22.0