[Qemu-devel] [PATCH v7 03/10] accel: replacing part of CONFIG_PROFILER with TBStats

[vandersonmr]

We add some of the statistics collected in the TCGProfiler
into the TBStats, having the statistics not only for the whole
emulation but for each TB. Then, we removed these stats
from TCGProfiler and reconstruct the information for the
"info jit" using the sum of all TBStats statistics.

The goal is to have one unique and better way of collecting
emulation statistics. Moreover, checking dynamiclly if the
profiling is enabled showed to have an insignificant impact
on the performance:
https://wiki.qemu.org/Internships/ProjectIdeas/TCGCodeQuality#Overheads.

Reviewed-by: Alex Bennée <address@hidden>
Signed-off-by: Vanderson M. do Rosario <address@hidden>
---
 accel/tcg/tb-stats.c      | 96 +++++++++++++++++++++++++++++++++++++++
 accel/tcg/translate-all.c |  8 +---
 include/exec/tb-stats.h   | 11 +++++
 tcg/tcg.c                 | 93 ++++---------------------------------
 tcg/tcg.h                 | 10 ----
 5 files changed, 119 insertions(+), 99 deletions(-)

diff --git a/accel/tcg/tb-stats.c b/accel/tcg/tb-stats.c
index 1db81d83e7..176da60e13 100644
--- a/accel/tcg/tb-stats.c
+++ b/accel/tcg/tb-stats.c
@@ -25,9 +25,105 @@
 #include "qemu/osdep.h"
 
 #include "disas/disas.h"
+#include "exec/exec-all.h"
+#include "tcg.h"
+
+#include "qemu/qemu-print.h"
 
 #include "exec/tb-stats.h"
 
+struct jit_profile_info {
+    uint64_t translations;
+    uint64_t aborted;
+    uint64_t ops;
+    unsigned ops_max;
+    uint64_t del_ops;
+    uint64_t temps;
+    unsigned temps_max;
+    uint64_t host;
+    uint64_t guest;
+    uint64_t search_data;
+};
+
+/* accumulate the statistics from all TBs */
+static void collect_jit_profile_info(void *p, uint32_t hash, void *userp)
+{
+    struct jit_profile_info *jpi = userp;
+    TBStatistics *tbs = p;
+
+    jpi->translations += tbs->translations.total;
+    jpi->ops += tbs->code.num_tcg_ops;
+    if (stat_per_translation(tbs, code.num_tcg_ops) > jpi->ops_max) {
+        jpi->ops_max = stat_per_translation(tbs, code.num_tcg_ops);
+    }
+    jpi->del_ops += tbs->code.deleted_ops;
+    jpi->temps += tbs->code.temps;
+    if (stat_per_translation(tbs, code.temps) > jpi->temps_max) {
+        jpi->temps_max = stat_per_translation(tbs, code.temps);
+    }
+    jpi->host += tbs->code.out_len;
+    jpi->guest += tbs->code.in_len;
+    jpi->search_data += tbs->code.search_out_len;
+}
+
+/* dump JIT statisticis using TCGProfile and TBStats */
+void dump_jit_profile_info(TCGProfile *s)
+{
+    if (!tb_stats_collection_enabled()) {
+        return;
+    }
+
+    struct jit_profile_info *jpi = g_new0(struct jit_profile_info, 1);
+
+    qht_iter(&tb_ctx.tb_stats, collect_jit_profile_info, jpi);
+
+    if (jpi->translations) {
+        qemu_printf("translated TBs      %" PRId64 "\n", jpi->translations);
+        qemu_printf("avg ops/TB          %0.1f max=%d\n",
+                jpi->ops / (double) jpi->translations, jpi->ops_max);
+        qemu_printf("deleted ops/TB      %0.2f\n",
+                jpi->del_ops / (double) jpi->translations);
+        qemu_printf("avg temps/TB        %0.2f max=%d\n",
+                jpi->temps / (double) jpi->translations, jpi->temps_max);
+        qemu_printf("avg host code/TB    %0.1f\n",
+                jpi->host / (double) jpi->translations);
+        qemu_printf("avg search data/TB  %0.1f\n",
+                jpi->search_data / (double) jpi->translations);
+
+        if (s) {
+            int64_t tot = s->interm_time + s->code_time;
+            qemu_printf("JIT cycles          %" PRId64 " (%0.3f s at 2.4 
GHz)\n",
+                            tot, tot / 2.4e9);
+            qemu_printf("cycles/op           %0.1f\n",
+                        jpi->ops ? (double)tot / jpi->ops : 0);
+            qemu_printf("cycles/in byte      %0.1f\n",
+                        jpi->guest ? (double)tot / jpi->guest : 0);
+            qemu_printf("cycles/out byte     %0.1f\n",
+                        jpi->host ? (double)tot / jpi->host : 0);
+            qemu_printf("cycles/search byte     %0.1f\n",
+                        jpi->search_data ? (double)tot / jpi->search_data : 0);
+            if (tot == 0) {
+                tot = 1;
+            }
+            qemu_printf("  gen_interm time   %0.1f%%\n",
+                        (double)s->interm_time / tot * 100.0);
+            qemu_printf("  gen_code time     %0.1f%%\n",
+                        (double)s->code_time / tot * 100.0);
+            qemu_printf("optim./code time    %0.1f%%\n",
+                        (double)s->opt_time / (s->code_time ? s->code_time : 1)
+                        * 100.0);
+            qemu_printf("liveness/code time  %0.1f%%\n",
+                    (double)s->la_time / (s->code_time ? s->code_time : 1) * 
100.0);
+            qemu_printf("cpu_restore count   %" PRId64 "\n",
+                    s->restore_count);
+            qemu_printf("  avg cycles        %0.1f\n",
+                    s->restore_count ? (double)s->restore_time / 
s->restore_count : 0);
+        }
+    }
+    g_free(jpi);
+}
+
+
 void init_tb_stats_htable_if_not(void)
 {
     if (tb_stats_collection_enabled() && !tb_ctx.tb_stats.map) {
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index fb2fe0fa1f..fe890f0782 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -1774,8 +1774,6 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
  tb_overflow:
 
 #ifdef CONFIG_PROFILER
-    /* includes aborted translations because of exceptions */
-    atomic_set(&prof->tb_count1, prof->tb_count1 + 1);
     ti = profile_getclock();
 #endif
 
@@ -1823,7 +1821,6 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
     }
 
 #ifdef CONFIG_PROFILER
-    atomic_set(&prof->tb_count, prof->tb_count + 1);
     atomic_set(&prof->interm_time, prof->interm_time + profile_getclock() - 
ti);
     ti = profile_getclock();
 #endif
@@ -1870,13 +1867,12 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
 
 #ifdef CONFIG_PROFILER
     atomic_set(&prof->code_time, prof->code_time + profile_getclock() - ti);
-    atomic_set(&prof->code_in_len, prof->code_in_len + tb->size);
-    atomic_set(&prof->code_out_len, prof->code_out_len + gen_code_size);
-    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.in_len, tb->size);
         atomic_add(&tb->tb_stats->code.out_len, gen_code_size);
+        atomic_add(&tb->tb_stats->code.search_out_len, search_size);
     }
 
 #ifdef DEBUG_DISAS
diff --git a/include/exec/tb-stats.h b/include/exec/tb-stats.h
index b68edd5d24..b9d5a343be 100644
--- a/include/exec/tb-stats.h
+++ b/include/exec/tb-stats.h
@@ -33,6 +33,9 @@
 #define tb_stats_enabled(tb, JIT_STATS) \
     (tb && tb->tb_stats && (tb->tb_stats->stats_enabled & JIT_STATS))
 
+#define stat_per_translation(stat, name) \
+    (stat->translations.total ? stat->name / stat->translations.total : 0)
+
 typedef struct TBStatistics TBStatistics;
 
 /*
@@ -63,7 +66,13 @@ struct TBStatistics {
         unsigned num_tcg_ops;
         unsigned num_tcg_ops_opt;
         unsigned spills;
+
+        /* CONFIG_PROFILE */
+        unsigned temps;
+        unsigned deleted_ops;
+        unsigned in_len;
         unsigned out_len;
+        unsigned search_out_len;
     } code;
 
     struct {
@@ -80,6 +89,8 @@ bool tb_stats_cmp(const void *ap, const void *bp);
 
 void init_tb_stats_htable_if_not(void);
 
+void dump_jit_profile_info(TCGProfile *s);
+
 /* TBStatistic collection controls */
 enum TBStatsStatus { TB_STATS_RUNNING, TB_STATS_PAUSED, TB_STATS_STOPPED };
 
diff --git a/tcg/tcg.c b/tcg/tcg.c
index ae3e7a2217..03b11495aa 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -2294,9 +2294,9 @@ void tcg_op_remove(TCGContext *s, TCGOp *op)
     QTAILQ_INSERT_TAIL(&s->free_ops, op, link);
     s->nb_ops--;
 
-#ifdef CONFIG_PROFILER
-    atomic_set(&s->prof.del_op_count, s->prof.del_op_count + 1);
-#endif
+    if (tb_stats_enabled(s->current_tb, TB_JIT_STATS)) {
+        atomic_inc(&s->current_tb->tb_stats->code.deleted_ops);
+    }
 }
 
 static TCGOp *tcg_op_alloc(TCGOpcode opc)
@@ -3913,16 +3913,6 @@ void tcg_profile_snapshot(TCGProfile *prof, bool 
counters, bool table)
 
         if (counters) {
             PROF_ADD(prof, orig, cpu_exec_time);
-            PROF_ADD(prof, orig, tb_count1);
-            PROF_ADD(prof, orig, tb_count);
-            PROF_ADD(prof, orig, op_count);
-            PROF_MAX(prof, orig, op_count_max);
-            PROF_ADD(prof, orig, temp_count);
-            PROF_MAX(prof, orig, temp_count_max);
-            PROF_ADD(prof, orig, del_op_count);
-            PROF_ADD(prof, orig, code_in_len);
-            PROF_ADD(prof, orig, code_out_len);
-            PROF_ADD(prof, orig, search_out_len);
             PROF_ADD(prof, orig, interm_time);
             PROF_ADD(prof, orig, code_time);
             PROF_ADD(prof, orig, la_time);
@@ -4002,26 +3992,17 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
     TCGOp *op;
 
     s->current_tb = tb;
-
-#ifdef CONFIG_PROFILER
-    {
+    if (tb_stats_enabled(tb, TB_JIT_STATS)) {
         int n = 0;
 
         QTAILQ_FOREACH(op, &s->ops, link) {
             n++;
         }
-        atomic_set(&prof->op_count, prof->op_count + n);
-        if (n > prof->op_count_max) {
-            atomic_set(&prof->op_count_max, n);
-        }
+        atomic_add(&tb->tb_stats->code.num_tcg_ops, n);
 
         n = s->nb_temps;
-        atomic_set(&prof->temp_count, prof->temp_count + n);
-        if (n > prof->temp_count_max) {
-            atomic_set(&prof->temp_count_max, n);
-        }
+        atomic_add(&tb->tb_stats->code.temps, n);
     }
-#endif
 
 #ifdef DEBUG_DISAS
     if (unlikely(qemu_loglevel_mask(CPU_LOG_TB_OP)
@@ -4228,70 +4209,16 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb)
     return tcg_current_code_size(s);
 }
 
-#ifdef CONFIG_PROFILER
 void tcg_dump_info(void)
 {
+    TCGProfile *s = NULL;
+#ifdef CONFIG_PROFILER
     TCGProfile prof = {};
-    const TCGProfile *s;
-    int64_t tb_count;
-    int64_t tb_div_count;
-    int64_t tot;
-
     tcg_profile_snapshot_counters(&prof);
     s = &prof;
-    tb_count = s->tb_count;
-    tb_div_count = tb_count ? tb_count : 1;
-    tot = s->interm_time + s->code_time;
-
-    qemu_printf("JIT cycles          %" PRId64 " (%0.3f s at 2.4 GHz)\n",
-                tot, tot / 2.4e9);
-    qemu_printf("translated TBs      %" PRId64 " (aborted=%" PRId64
-                " %0.1f%%)\n",
-                tb_count, s->tb_count1 - tb_count,
-                (double)(s->tb_count1 - s->tb_count)
-                / (s->tb_count1 ? s->tb_count1 : 1) * 100.0);
-    qemu_printf("avg ops/TB          %0.1f max=%d\n",
-                (double)s->op_count / tb_div_count, s->op_count_max);
-    qemu_printf("deleted ops/TB      %0.2f\n",
-                (double)s->del_op_count / tb_div_count);
-    qemu_printf("avg temps/TB        %0.2f max=%d\n",
-                (double)s->temp_count / tb_div_count, s->temp_count_max);
-    qemu_printf("avg host code/TB    %0.1f\n",
-                (double)s->code_out_len / tb_div_count);
-    qemu_printf("avg search data/TB  %0.1f\n",
-                (double)s->search_out_len / tb_div_count);
-    
-    qemu_printf("cycles/op           %0.1f\n",
-                s->op_count ? (double)tot / s->op_count : 0);
-    qemu_printf("cycles/in byte      %0.1f\n",
-                s->code_in_len ? (double)tot / s->code_in_len : 0);
-    qemu_printf("cycles/out byte     %0.1f\n",
-                s->code_out_len ? (double)tot / s->code_out_len : 0);
-    qemu_printf("cycles/search byte     %0.1f\n",
-                s->search_out_len ? (double)tot / s->search_out_len : 0);
-    if (tot == 0) {
-        tot = 1;
-    }
-    qemu_printf("  gen_interm time   %0.1f%%\n",
-                (double)s->interm_time / tot * 100.0);
-    qemu_printf("  gen_code time     %0.1f%%\n",
-                (double)s->code_time / tot * 100.0);
-    qemu_printf("optim./code time    %0.1f%%\n",
-                (double)s->opt_time / (s->code_time ? s->code_time : 1)
-                * 100.0);
-    qemu_printf("liveness/code time  %0.1f%%\n",
-                (double)s->la_time / (s->code_time ? s->code_time : 1) * 
100.0);
-    qemu_printf("cpu_restore count   %" PRId64 "\n",
-                s->restore_count);
-    qemu_printf("  avg cycles        %0.1f\n",
-                s->restore_count ? (double)s->restore_time / s->restore_count 
: 0);
-}
-#else
-void tcg_dump_info(void)
-{
-    qemu_printf("[TCG profiler not compiled]\n");
-}
 #endif
+    dump_jit_profile_info(s);
+}
 
 #ifdef ELF_HOST_MACHINE
 /* In order to use this feature, the backend needs to do three things:
diff --git a/tcg/tcg.h b/tcg/tcg.h
index b4601162f8..a8d779f7e6 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -646,16 +646,6 @@ QEMU_BUILD_BUG_ON(NB_OPS > (1 << 8));
 
 typedef struct TCGProfile {
     int64_t cpu_exec_time;
-    int64_t tb_count1;
-    int64_t tb_count;
-    int64_t op_count; /* total insn count */
-    int op_count_max; /* max insn per TB */
-    int temp_count_max;
-    int64_t temp_count;
-    int64_t del_op_count;
-    int64_t code_in_len;
-    int64_t code_out_len;
-    int64_t search_out_len;
     int64_t interm_time;
     int64_t code_time;
     int64_t la_time;
-- 
2.22.0