[Qemu-devel] [PATCH v6 07/10] monitor: adding tb_stats hmp command

[vandersonmr <vandersonmr2@gmail.com>]

Adding tb_stats [start|pause|stop|filter] command to hmp.
This allows controlling the collection of statistics.
It is also possible to set the level of collection:
all, jit, or exec.

tb_stats filter allow to only collect statistics for the TB
in the last_search list.

The goal of this command is to allow the dynamic exploration
of the TCG behavior and quality. Therefore, for now, a
corresponding QMP command is not worthwhile.

Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Vanderson M. do Rosario <vandersonmr2@gmail.com>
---
 accel/tcg/tb-stats.c    | 111 ++++++++++++++++++++++++++++++++++++++++
 hmp-commands.hx         |  17 ++++++
 include/exec/tb-stats.h |  12 +++++
 include/qemu-common.h   |   1 +
 monitor/misc.c          |  49 ++++++++++++++++++
 vl.c                    |   6 +++
 6 files changed, 196 insertions(+)

diff --git a/accel/tcg/tb-stats.c b/accel/tcg/tb-stats.c
index 8554174360..ffaa9d5d51 100644
--- a/accel/tcg/tb-stats.c
+++ b/accel/tcg/tb-stats.c
@@ -9,6 +9,9 @@
 
 #include "exec/tb-stats.h"
 
+/* only accessed in safe work */
+static GList *last_search;
+
 uint64_t dev_time;
 
 struct jit_profile_info {
@@ -137,6 +140,96 @@ void dump_jit_profile_info(TCGProfile *s)
     g_free(jpi);
 }
 
+static void free_tbstats(void *p, uint32_t hash, void *userp)
+{
+    g_free(p);
+}
+
+static void clean_tbstats(void)
+{
+    /* remove all tb_stats */
+    qht_iter(&tb_ctx.tb_stats, free_tbstats, NULL);
+    qht_destroy(&tb_ctx.tb_stats);
+}
+
+void do_hmp_tbstats_safe(CPUState *cpu, run_on_cpu_data icmd)
+{
+    struct TbstatsCommand *cmdinfo = icmd.host_ptr;
+    int cmd = cmdinfo->cmd;
+    uint32_t level = cmdinfo->level;
+
+    switch (cmd) {
+    case START:
+        if (tb_stats_collection_paused()) {
+            set_tbstats_flags(level);
+        } else {
+            if (tb_stats_collection_enabled()) {
+                qemu_printf("TB information already being recorded");
+                return;
+            }
+            qht_init(&tb_ctx.tb_stats, tb_stats_cmp, CODE_GEN_HTABLE_SIZE,
+                        QHT_MODE_AUTO_RESIZE);
+        }
+
+        set_default_tbstats_flag(level);
+        enable_collect_tb_stats();
+        tb_flush(cpu);
+        break;
+    case PAUSE:
+        if (!tb_stats_collection_enabled()) {
+            qemu_printf("TB information not being recorded");
+            return;
+        }
+
+        /* Continue to create TBStatistic structures but stop collecting statistics */
+        pause_collect_tb_stats();
+        set_default_tbstats_flag(TB_NOTHING);
+        set_tbstats_flags(TB_PAUSED);
+        tb_flush(cpu);
+        break;
+    case STOP:
+        if (!tb_stats_collection_enabled()) {
+            qemu_printf("TB information not being recorded");
+            return;
+        }
+
+        /* Dissalloc all TBStatistics structures and stop creating new ones */
+        disable_collect_tb_stats();
+        clean_tbstats();
+        tb_flush(cpu);
+        break;
+    case FILTER:
+        if (!tb_stats_collection_enabled()) {
+            qemu_printf("TB information not being recorded");
+            return;
+        }
+        if (!last_search) {
+            qemu_printf("no search on record! execute info tbs before filtering!");
+            return;
+        }
+
+        set_default_tbstats_flag(TB_NOTHING);
+
+        /* Set all tbstats as paused, then return only the ones from last_search */
+        pause_collect_tb_stats();
+        set_tbstats_flags(TB_PAUSED);
+
+        for (GList *iter = last_search; iter; iter = g_list_next(iter)) {
+            TBStatistics *tbs = iter->data;
+            tbs->stats_enabled = level;
+        }
+
+        tb_flush(cpu);
+
+        break;
+    default: /* INVALID */
+        g_assert_not_reached();
+        break;
+    }
+
+    g_free(cmdinfo);
+}
+
 
 void init_tb_stats_htable_if_not(void)
 {
@@ -172,6 +265,24 @@ bool tb_stats_collection_paused(void)
     return tcg_collect_tb_stats == TB_STATS_PAUSED;
 }
 
+static void reset_tbstats_flag(void *p, uint32_t hash, void *userp)
+{
+    uint32_t flag = *((int *)userp);
+    TBStatistics *tbs = p;
+    tbs->stats_enabled = flag;
+}
+
+void set_default_tbstats_flag(uint32_t flag)
+{
+    default_tbstats_flag = flag;
+}
+
+void set_tbstats_flags(uint32_t flag)
+{
+    /* iterate over tbstats setting their flag as TB_NOTHING */
+    qht_iter(&tb_ctx.tb_stats, reset_tbstats_flag, &flag);
+}
+
 uint32_t get_default_tbstats_flag(void)
 {
     return default_tbstats_flag;
diff --git a/hmp-commands.hx b/hmp-commands.hx
index bfa5681dd2..419898751e 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1885,6 +1885,23 @@ STEXI
 @findex qemu-io
 Executes a qemu-io command on the given block device.
 
+ETEXI
+#if defined(CONFIG_TCG)
+    {
+        .name       = "tb_stats",
+        .args_type  = "command:s,level:s?",
+        .params     = "command [stats_level]",
+        .help       = "Control tb statistics collection:"
+                        "tb_stats (start|pause|stop|filter) [all|jit_stats|exec_stats]",
+        .cmd        = hmp_tbstats,
+    },
+#endif
+
+STEXI
+@item tb_stats
+@findex
+Control recording tb statistics
+
 ETEXI
 
     {
diff --git a/include/exec/tb-stats.h b/include/exec/tb-stats.h
index a607ceaa53..b57324fc1a 100644
--- a/include/exec/tb-stats.h
+++ b/include/exec/tb-stats.h
@@ -6,6 +6,9 @@
 #include "exec/tb-context.h"
 #include "tcg.h"
 
+enum SortBy { SORT_BY_HOTNESS, SORT_BY_HG /* Host/Guest */, SORT_BY_SPILLS };
+enum TbstatsCmd { START, PAUSE, STOP, FILTER };
+
 #define tb_stats_enabled(tb, JIT_STATS) \
     (tb && tb->tb_stats && (tb->tb_stats->stats_enabled & JIT_STATS))
 
@@ -74,10 +77,18 @@ bool tb_stats_cmp(const void *ap, const void *bp);
 
 void dump_jit_exec_time_info(uint64_t dev_time);
 
+void set_tbstats_flags(uint32_t flags);
 void init_tb_stats_htable_if_not(void);
 
 void dump_jit_profile_info(TCGProfile *s);
 
+struct TbstatsCommand {
+    enum TbstatsCmd cmd;
+    uint32_t level;
+};
+
+void do_hmp_tbstats_safe(CPUState *cpu, run_on_cpu_data icmd);
+
 /* TBStatistic collection controls */
 void enable_collect_tb_stats(void);
 void disable_collect_tb_stats(void);
@@ -85,6 +96,7 @@ void pause_collect_tb_stats(void);
 bool tb_stats_collection_enabled(void);
 bool tb_stats_collection_paused(void);
 
+void set_default_tbstats_flag(uint32_t flag);
 uint32_t get_default_tbstats_flag(void);
 
 #endif
diff --git a/include/qemu-common.h b/include/qemu-common.h
index 3930b61ec0..d653c00d91 100644
--- a/include/qemu-common.h
+++ b/include/qemu-common.h
@@ -141,6 +141,7 @@ enum TBStatsStatus {
 #define TB_EXEC_STATS (1 << 1)
 #define TB_JIT_STATS  (1 << 2)
 #define TB_JIT_TIME   (1 << 3)
+#define TB_PAUSED     (1 << 4)
 
 extern int tcg_collect_tb_stats;
 extern uint32_t default_tbstats_flag;
diff --git a/monitor/misc.c b/monitor/misc.c
index 4839d6875f..6902e8addb 100644
--- a/monitor/misc.c
+++ b/monitor/misc.c
@@ -74,6 +74,8 @@
 #include "sysemu/cpus.h"
 #include "qemu/cutils.h"
 #include "tcg/tcg.h"
+#include "exec/tb-stats.h"
+#include "qemu-common.h"
 
 #if defined(TARGET_S390X)
 #include "hw/s390x/storage-keys.h"
@@ -459,6 +461,49 @@ static void hmp_info_registers(Monitor *mon, const QDict *qdict)
 }
 
 #ifdef CONFIG_TCG
+static void hmp_tbstats(Monitor *mon, const QDict *qdict)
+{
+    if (!tcg_enabled()) {
+        error_report("TB information is only available with accel=tcg");
+        return;
+    }
+
+    char *cmd = (char *) qdict_get_try_str(qdict, "command");
+    enum TbstatsCmd icmd = -1;
+
+    if (strcmp(cmd, "start") == 0) {
+        icmd = START;
+    } else if (strcmp(cmd, "pause") == 0) {
+        icmd = PAUSE;
+    } else if (strcmp(cmd, "stop") == 0) {
+        icmd = STOP;
+    } else if (strcmp(cmd, "filter") == 0) {
+        icmd = FILTER;
+    } else {
+        error_report("invalid command!");
+        return;
+    }
+
+    char *slevel = (char *) qdict_get_try_str(qdict, "level");
+    uint32_t level = TB_EXEC_STATS | TB_JIT_STATS | TB_JIT_TIME;
+    if (slevel) {
+        if (strcmp(slevel, "jit") == 0) {
+            level = TB_JIT_STATS;
+        } else if (strcmp(slevel, "exec") == 0) {
+            level = TB_EXEC_STATS;
+        } else if (strcmp(slevel, "time") == 0) {
+            level = TB_JIT_TIME;
+        }
+    }
+
+    struct TbstatsCommand *tbscommand = g_new0(struct TbstatsCommand, 1);
+    tbscommand->cmd = icmd;
+    tbscommand->level = level;
+    async_safe_run_on_cpu(first_cpu, do_hmp_tbstats_safe,
+                          RUN_ON_CPU_HOST_PTR(tbscommand));
+
+}
+
 static void hmp_info_jit(Monitor *mon, const QDict *qdict)
 {
     if (!tcg_enabled()) {
@@ -1089,8 +1134,12 @@ static void hmp_info_mtree(Monitor *mon, const QDict *qdict)
 
 static void hmp_info_profile(Monitor *mon, const QDict *qdict)
 {
+#ifdef CONFIG_TCG
     dump_jit_exec_time_info(dev_time);
     dev_time = 0;
+#else
+    error_report("TCG should be enabled!");
+#endif
 }
 
 /* Capture support */
diff --git a/vl.c b/vl.c
index ef7737a7bc..326090c36a 100644
--- a/vl.c
+++ b/vl.c
@@ -1781,11 +1781,17 @@ static bool main_loop_should_exit(void)
 
 static void main_loop(void)
 {
+#ifdef CONFIG_TCG
     uint64_t ti;
+#endif
     while (!main_loop_should_exit()) {
+#ifdef CONFIG_TCG
         ti = profile_getclock();
+#endif
         main_loop_wait(false);
+#ifdef CONFIG_TCG
         dev_time += profile_getclock() - ti;
+#endif
     }
 }
 
-- 
2.22.0