Re: [PATCH v17 11/16] accel/tcg: Add tb_stats_collect and tb_stats_dump

["Alex Bennée" <alex.bennee@linaro.org>]

Richard Henderson <richard.henderson@linaro.org> writes:

> From: "Vanderson M. do Rosario" <vandersonmr2@gmail.com>
>
> These functions will be used together to output statistics.
>
> Signed-off-by: Vanderson M. do Rosario <vandersonmr2@gmail.com>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Signed-off-by: Fei Wu <fei2.wu@intel.com>
> [rth: Split out of a larger patch]
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  include/tcg/tb-stats.h |  25 +++++++++
>  accel/tcg/tb-stats.c   | 119 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 144 insertions(+)
>
> diff --git a/include/tcg/tb-stats.h b/include/tcg/tb-stats.h
> index 1ec0d13eff..edee73b63b 100644
> --- a/include/tcg/tb-stats.h
> +++ b/include/tcg/tb-stats.h
> @@ -129,4 +129,29 @@ void tb_stats_reset_tbs(void);
>  TBStatistics *tb_stats_lookup(tb_page_addr_t phys_pc, vaddr pc,
>                                uint32_t flags, uint64_t flags2);
>  
> +/**
> + * tb_stats_collect:
> + * @max: maximum number of results
> + * @sort: sort function
> + *
> + * Collect all TBStatistics and return the first @max items,
> + * as dictated by the sort criteria.
> + */
> +GPtrArray *tb_stats_collect(unsigned max, GCompareFunc sort);
> +
> +/* Sort functions for tb_stats_collect. */
> +gint tb_stats_sort_by_spills(gconstpointer, gconstpointer);
> +gint tb_stats_sort_by_coverage(gconstpointer, gconstpointer);
> +gint tb_stats_sort_by_hg(gconstpointer, gconstpointer);
> +
> +/**
> + * tb_stats_dump:
> + * @s: structure to dump
> + * @index: label to emit
> + *
> + * Return a string with the rendering of the data in @s;
> + * @index is included in the output.
> + */
> +GString *tb_stats_dump(TBStatistics *s, unsigned index);
> +
>  #endif /* TCG_TB_STATS_H */
> diff --git a/accel/tcg/tb-stats.c b/accel/tcg/tb-stats.c
> index 424c9a90ec..b2c9445b67 100644
> --- a/accel/tcg/tb-stats.c
> +++ b/accel/tcg/tb-stats.c
> @@ -83,3 +83,122 @@ TBStatistics *tb_stats_lookup(tb_page_addr_t phys_pc, vaddr pc,
>      }
>      return s;
>  }
> +
> +static void tb_stats_collect_iter(void *p, uint32_t hash, void *u)
> +{
> +    g_ptr_array_add(u, p);
> +}
> +
> +static void calculate_coverages(GPtrArray *array)
> +{
> +    double total_exec_count = 0;
> +    guint i, n = array->len;
> +
> +    for (i = 0; i < n; ++i) {
> +        TBStatistics *s = g_ptr_array_index(array, i);
> +        double avg_insns = 1;
> +        double exec_count;
> +
> +        if (s->translations.total) {
> +            avg_insns = s->code.num_guest_inst / (double)s->translations.total;
> +        }
> +        exec_count = ((double)s->executions.atomic + s->executions.normal)
> +                     / avg_insns;
> +        s->executions.coverage = exec_count;
> +        total_exec_count += exec_count;
> +    }
> +
> +    for (i = 0; i < n; ++i) {
> +        TBStatistics *s = g_ptr_array_index(array, i);
> +        s->executions.coverage /= total_exec_count;
> +    }
> +}
> +
> +GPtrArray *tb_stats_collect(unsigned max, GCompareFunc sort)
> +{
> +    GPtrArray *array = g_ptr_array_new();
> +
> +    /*
> +     * Collect all TBStatistics and sort.
> +     * Note that coverage data requires both execution and jit collection.
> +     */
> +    qht_iter(&tb_ctx.stats, tb_stats_collect_iter, array);
> +    calculate_coverages(array);
> +    g_ptr_array_sort(array, sort);
> +
> +    /* Truncate to the first MAX entries. */
> +    if (max < array->len) {
> +        g_ptr_array_set_size(array, max);
> +    }
> +    return array;
> +}
> +
> +gint tb_stats_sort_by_spills(gconstpointer p1, gconstpointer p2)
> +{
> +    const TBStatistics *s1 = *(TBStatistics **)p1;
> +    const TBStatistics *s2 = *(TBStatistics **)p2;
> +    double c1 = (double)s1->code.spills / s1->translations.total;
> +    double c2 = (double)s2->code.spills / s2->translations.total;
> +
> +    return c1 < c2 ? 1 : c1 == c2 ? 0 : -1;
> +}
> +
> +gint tb_stats_sort_by_coverage(gconstpointer p1, gconstpointer p2)
> +{
> +    const TBStatistics *s1 = *(TBStatistics **)p1;
> +    const TBStatistics *s2 = *(TBStatistics **)p2;
> +    double c1 = s1->executions.coverage;
> +    double c2 = s2->executions.coverage;
> +
> +    return c1 < c2 ? 1 : c1 == c2 ? 0 : -1;
> +}
> +
> +gint tb_stats_sort_by_hg(gconstpointer p1, gconstpointer p2)
> +{
> +    const TBStatistics *s1 = *(TBStatistics **)p1;
> +    const TBStatistics *s2 = *(TBStatistics **)p2;
> +    double c1 = (double)s1->code.out_len / s1->code.num_guest_inst;
> +    double c2 = (double)s2->code.out_len / s2->code.num_guest_inst;
> +
> +    return c1 < c2 ? 1 : c1 == c2 ? 0 : -1;
> +}
> +
> +GString *tb_stats_dump(TBStatistics *s, unsigned index)
> +{
> +    unsigned n = s->tbs->len;
> +    unsigned invalid = 0;
> +    GString *buf;
> +
> +    for (unsigned i = 0; i < n; ++i) {
> +        TranslationBlock *tb = g_ptr_array_index(s->tbs, i);
> +        if (tb->cflags & CF_INVALID) {
> +            invalid += 1;
> +        }
> +    }
> +
> +    buf = g_string_new("");
> +    g_string_append_printf(buf,
> +        "TB id:%u | phys:0x" TB_PAGE_ADDR_FMT " virt=%" VADDR_PRIx
> +        " flags:0x%08x invalid:%u/%u\n",
> +        index, s->phys_pc, s->pc, s->flags, invalid, n - invalid);

This is a little unclear in the output maybe:

  flags:0x%08x translations:%u (of which %u invalidated)

and adjust the names appropriately?

> +
> +    if (tb_stats_enabled & TB_STATS_EXEC) {
> +        g_string_append_printf(buf,
> +            "\t| exec:%lu/%lu coverage:%.2f%%\n",
> +            s->executions.normal, s->executions.atomic,
> +            s->executions.coverage * 100);
> +    }
> +
> +    if (tb_stats_enabled & TB_STATS_JIT) {
> +        g_string_append_printf(buf,
> +            "\t| trans:%lu inst: g:%lu op:%lu op_opt:%lu spills:%ld\n"
> +            "\t| h/g (host bytes / guest insts): %f\n",
> +            s->translations.total,
> +            s->code.num_guest_inst / s->translations.total,
> +            s->code.num_tcg_ops / s->translations.total,
> +            s->code.num_tcg_ops_opt / s->translations.total,
> +            s->code.spills / s->translations.total,
> +            (double)s->code.out_len / s->code.num_guest_inst);
> +    }
> +    return buf;
> +}


-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro