Em Tue, Dec 08, 2015 at 11:47:06PM +0100, Jiri Olsa escreveu:
> Together with adding cconf->base_offset to sums used
> for cacheline computation, this ensures proper cacheline
> number to be printed for nested struct. Note possitions
> of 'cacheline' lines in following outputs.
>
> Before:
> $ pahole -C task_struct -E ~/kernel/linux-perf-local/vmlinux
> struct task_struct {
> volatile long int state; /* 0 8 */
>
> --- First cacheline is ok
>
> struct task_struct * last_wakee; /* 56 8 */
> /* --- cacheline 1 boundary (64 bytes) --- */
> int wake_cpu; /* 64 4 */
>
> ...
>
> const struct sched_class * sched_class; /* 88 8 */
> struct sched_entity {
> struct load_weight {
> long unsigned int weight; /* 96 8 */
> /* typedef u32 */ unsigned int inv_weight; /* 104 4 */
> } load; /* 96 16 */
>
> --- Second one is still in relative mode and gives wrong
> alignment in wrt task_struct start
>
> unsigned int on_rq; /* 152 4 */
> /* --- cacheline 1 boundary (64 bytes) --- */
Ok, this is a bug...
> /* typedef u64 */ long long unsigned int exec_start; /* 160 8 */
> /* typedef u64 */ long long unsigned int sum_exec_runtime; /* 168 8 */
> ...
>
> After:
> $ pahole -C task_struct -E ~/kernel/linux-perf-local/vmlinux
>
> struct task_struct {
> volatile long int state; /* 0 8 */
>
> --- First cacheline is ok
>
> struct task_struct * last_wakee; /* 56 8 */
> /* --- cacheline 1 boundary (64 bytes) --- */
> int wake_cpu; /* 64 4 */
>
> ...
>
> const struct sched_class * sched_class; /* 88 8 */
> struct sched_entity {
> struct load_weight {
> long unsigned int weight; /* 96 8 */
> /* typedef u32 */ unsigned int inv_weight; /* 104 4 */
> } load; /* 96 16 */
> struct rb_node {
> long unsigned int __rb_parent_color; /* 112 8 */
> struct rb_node * rb_right; /* 120 8 */
> /* --- cacheline 2 boundary (128 bytes) --- */
Which seems fixed here, but...
> struct rb_node * rb_left; /* 128 8 */
> } run_node; /* 112 24 */
>
> --- Second one is still in relative mode and gives wrong
> alignment in wrt task_struct start
... why this one is buggy still? I.e. it should be fixed in such a way
that when we go recursively expanding structs, we know what is the
current cacheline we're on.
- Arnaldo
>
> /* --- cacheline 2 boundary (128 bytes) was 8 bytes ago --- */
> struct list_head {
> struct list_head * next; /* 136 8 */
> struct list_head * prev; /* 144 8 */
> } group_node; /* 136 16 */
> ...
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> dwarves.h | 1 +
> dwarves_fprintf.c | 25 ++++++++++---------------
> 2 files changed, 11 insertions(+), 15 deletions(-)
>
> diff --git a/dwarves.h b/dwarves.h
> index 73fec8ac614a..44ebf8384b9c 100644
> --- a/dwarves.h
> +++ b/dwarves.h
> @@ -56,6 +56,7 @@ struct conf_fprintf {
> int32_t type_spacing;
> int32_t name_spacing;
> uint32_t base_offset;
> + uint32_t base_cacheline;
> uint8_t indent;
> uint8_t expand_types:1;
> uint8_t expand_pointers:1;
> diff --git a/dwarves_fprintf.c b/dwarves_fprintf.c
> index 2d114210831a..72d8b08bf235 100644
> --- a/dwarves_fprintf.c
> +++ b/dwarves_fprintf.c
> @@ -1118,22 +1118,21 @@ size_t function__fprintf_stats(const struct tag *tag, const struct cu *cu,
> return printed + fprintf(fp, " */\n");
> }
>
> -static size_t class__fprintf_cacheline_boundary(uint32_t last_cacheline,
> - size_t sum, size_t sum_holes,
> +static size_t class__fprintf_cacheline_boundary(size_t sum, size_t sum_holes,
> uint8_t *newline,
> - uint32_t *cacheline,
> struct conf_fprintf *cconf,
> FILE *fp)
> {
> - const size_t real_sum = sum + sum_holes;
> + const size_t real_sum = sum + sum_holes + cconf->base_offset;
> size_t printed = 0;
> + uint32_t cacheline = real_sum / cacheline_size;
>
> - *cacheline = real_sum / cacheline_size;
> -
> - if (*cacheline > last_cacheline) {
> + if (cacheline != cconf->base_cacheline) {
> const uint32_t cacheline_pos = real_sum % cacheline_size;
> const uint32_t cacheline_in_bytes = real_sum - cacheline_pos;
>
> + cconf->base_cacheline = cacheline;
> +
> if (*newline) {
> fputc('\n', fp);
> *newline = 0;
> @@ -1144,12 +1143,12 @@ static size_t class__fprintf_cacheline_boundary(uint32_t last_cacheline,
>
> if (cacheline_pos == 0)
> printed += fprintf(fp, "/* --- cacheline %u boundary "
> - "(%u bytes) --- */\n", *cacheline,
> + "(%u bytes) --- */\n", cacheline,
> cacheline_in_bytes);
> else
> printed += fprintf(fp, "/* --- cacheline %u boundary "
> "(%u bytes) was %u bytes ago --- "
> - "*/\n", *cacheline,
> + "*/\n", cacheline,
> cacheline_in_bytes, cacheline_pos);
> }
> return printed;
> @@ -1284,10 +1283,8 @@ size_t class__fprintf(struct class *class, const struct cu *cu,
> pos->byte_offset != last->byte_offset &&
> !cconf.suppress_comments)
> printed +=
> - class__fprintf_cacheline_boundary(last_cacheline,
> - sum, sum_holes,
> + class__fprintf_cacheline_boundary(sum, sum_holes,
> &newline,
> - &last_cacheline,
> &cconf,
> fp);
> /*
> @@ -1474,10 +1471,8 @@ size_t class__fprintf(struct class *class, const struct cu *cu,
> }
>
> if (!cconf.suppress_comments)
> - printed += class__fprintf_cacheline_boundary(last_cacheline,
> - sum, sum_holes,
> + printed += class__fprintf_cacheline_boundary(sum, sum_holes,
> &newline,
> - &last_cacheline,
> &cconf, fp);
> if (!cconf.show_only_data_members)
> class__vtable_fprintf(class, cu, &cconf, fp);
> --
> 2.4.3
>
> --
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