Re: [PATCH v12 10/15] monitor: adding tb_stats hmp command

["Wu, Fei" <fei2.wu@intel.com>]

On 5/18/2023 9:57 PM, Fei Wu wrote:
> From: "Vanderson M. do Rosario" <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>
> Message-Id: <20190829173437.5926-8-vandersonmr2@gmail.com>
> Message-Id: <20190829173437.5926-9-vandersonmr2@gmail.com>
> [AJB: fix authorship]
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Signed-off-by: Fei Wu <fei2.wu@intel.com>
> ---
>  accel/tcg/monitor.c           |  45 ++++++++++++++
>  accel/tcg/tb-stats.c          | 112 ++++++++++++++++++++++++++++++++++
>  hmp-commands.hx               |  16 +++++
>  include/exec/tb-stats-flags.h |   1 +
>  include/exec/tb-stats.h       |  10 +++
>  include/monitor/hmp.h         |   1 +
>  softmmu/runstate.c            |   6 ++
>  7 files changed, 191 insertions(+)
> 
> diff --git a/accel/tcg/monitor.c b/accel/tcg/monitor.c
> index 2bc87f2642..2e00f10267 100644
> --- a/accel/tcg/monitor.c
> +++ b/accel/tcg/monitor.c
> @@ -11,7 +11,9 @@
>  #include "qapi/error.h"
>  #include "qapi/type-helpers.h"
>  #include "qapi/qapi-commands-machine.h"
> +#include "qapi/qmp/qdict.h"
>  #include "monitor/monitor.h"
> +#include "monitor/hmp.h"
>  #include "sysemu/cpus.h"
>  #include "sysemu/cpu-timers.h"
>  #include "sysemu/tcg.h"
> @@ -87,6 +89,49 @@ HumanReadableText *qmp_x_query_opcount(Error **errp)
>  }
>  
>  #ifdef CONFIG_TCG
> +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));
> +
> +}
> +
>  HumanReadableText *qmp_x_query_profile(Error **errp)
>  {
>      g_autoptr(GString) buf = g_string_new("");
> diff --git a/accel/tcg/tb-stats.c b/accel/tcg/tb-stats.c
> index 68ac7d3f73..55afe6e489 100644
> --- a/accel/tcg/tb-stats.c
> +++ b/accel/tcg/tb-stats.c
> @@ -16,6 +16,7 @@
>  #include "qemu/timer.h"
>  
>  #include "exec/tb-stats.h"
> +#include "exec/tb-flush.h"
>  #include "tb-context.h"
>  
>  /* TBStatistic collection controls */
> @@ -28,6 +29,8 @@ enum TBStatsStatus {
>  
>  static enum TBStatsStatus tcg_collect_tb_stats;
>  static uint32_t default_tbstats_flag;
> +/* only accessed in safe work */
> +static GList *last_search;
>  
>  uint64_t dev_time;
>  
> @@ -170,6 +173,102 @@ void dump_jit_profile_info(TCGProfile *s, GString *buf)
>      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()) {

This check looks not enough, it will result in STOP as a nop after
PAUSE. And do we need a STATUS cmd to report current status?

Thanks,
Fei.
> +            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(void)
>  {
>      if (!tb_ctx.tb_stats.map && tb_stats_collection_enabled()) {
> @@ -204,6 +303,19 @@ 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_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 2cbd0f77a0..9a40215d34 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -1670,6 +1670,22 @@ SRST
>    Executes a qemu-io command on the given block device.
>  ERST
>  
> +#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
> +
> +SRST
> +``tb_stats`` *command* *stats_level*
> +  Control recording tb statistics
> +ERST
> +
>      {
>          .name       = "qom-list",
>          .args_type  = "path:s?",
> diff --git a/include/exec/tb-stats-flags.h b/include/exec/tb-stats-flags.h
> index 04adaee8d9..8c7abb62e5 100644
> --- a/include/exec/tb-stats-flags.h
> +++ b/include/exec/tb-stats-flags.h
> @@ -16,6 +16,7 @@
>  #define TB_JIT_STATS  (1 << 2)
>  #define TB_JIT_TIME   (1 << 3)
>  #define TB_ALL_STATS  (TB_EXEC_STATS | TB_JIT_STATS | TB_JIT_TIME)
> +#define TB_PAUSED     (1 << 4)
>  
>  /* TBStatistic collection controls */
>  void enable_collect_tb_stats(void);
> diff --git a/include/exec/tb-stats.h b/include/exec/tb-stats.h
> index 72585c448a..4bb343870b 100644
> --- a/include/exec/tb-stats.h
> +++ b/include/exec/tb-stats.h
> @@ -33,6 +33,9 @@
>  
>  #include "exec/tb-stats-flags.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))
>  
> @@ -114,4 +117,11 @@ void init_tb_stats_htable(void);
>  void dump_jit_profile_info(TCGProfile *s, GString *buf);
>  void dump_jit_exec_time_info(uint64_t dev_time, GString *buf);
>  
> +struct TbstatsCommand {
> +    enum TbstatsCmd cmd;
> +    uint32_t level;
> +};
> +
> +void do_hmp_tbstats_safe(CPUState *cpu, run_on_cpu_data icmd);
> +
>  #endif
> diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
> index 13f9a2dedb..2e7f141754 100644
> --- a/include/monitor/hmp.h
> +++ b/include/monitor/hmp.h
> @@ -181,5 +181,6 @@ void hmp_ioport_write(Monitor *mon, const QDict *qdict);
>  void hmp_boot_set(Monitor *mon, const QDict *qdict);
>  void hmp_info_mtree(Monitor *mon, const QDict *qdict);
>  void hmp_info_cryptodev(Monitor *mon, const QDict *qdict);
> +void hmp_tbstats(Monitor *mon, const QDict *qdict);
>  
>  #endif
> diff --git a/softmmu/runstate.c b/softmmu/runstate.c
> index 392e03c906..37390799f1 100644
> --- a/softmmu/runstate.c
> +++ b/softmmu/runstate.c
> @@ -728,12 +728,18 @@ static bool main_loop_should_exit(int *status)
>  int qemu_main_loop(void)
>  {
>      int status = EXIT_SUCCESS;
> +#ifdef CONFIG_TCG
>      uint64_t ti;
> +#endif
>  
>      while (!main_loop_should_exit(&status)) {
> +#ifdef CONFIG_TCG
>          ti = profile_getclock();
> +#endif
>          main_loop_wait(false);
> +#ifdef CONFIG_TCG
>          dev_time += profile_getclock() - ti;
> +#endif
>      }
>  
>      return status;