[PATCH v3 0/4] malloc: Reduce size by initializing data at runtime

[Simon Glass]

Hi Sean,

On Thu, 28 Sept 2023 at 08:45, Sean Anderson <sean.anderson at seco.com> wrote:
>
> In my efforts to get SPL to fit into flash after some changes I made, I
> noticed that av_ is one of the largest variables in SPL. As it turns
> out, we can generate it at runtime, and the code is already there. This
> has the potential to save 1-2k across the board, for some (very) minor
> boot time increase.
>
> This series is based on [1], since this makes checking for SYS_MALLOC_F
> easier. Passing CI at [2].
>
> To measure the boot time difference, I applied the following patch:
>
> ---
>  common/board_r.c | 5 +++++
>  common/spl/spl.c | 4 ++++
>  2 files changed, 9 insertions(+)
>
> diff --git a/common/board_r.c b/common/board_r.c
> index 58a5986aa54..ca624b20d46 100644
> --- a/common/board_r.c
> +++ b/common/board_r.c
> @@ -194,6 +194,7 @@ static int initr_barrier(void)
>         return 0;
>  }
>
> +static ulong malloc_begin, malloc_end;
>  static int initr_malloc(void)
>  {
>         ulong malloc_start;
> @@ -208,8 +209,10 @@ static int initr_malloc(void)
>          * reserve_noncached().
>          */
>         malloc_start = gd->relocaddr - TOTAL_MALLOC_LEN;
> +       malloc_begin = timer_get_boot_us();

Perhaps this would be better done with bootstage, since then the
timing can be enabled / disabled, and reported along with other
timings.


>         mem_malloc_init((ulong)map_sysmem(malloc_start, TOTAL_MALLOC_LEN),
>                         TOTAL_MALLOC_LEN);
> +       malloc_end = timer_get_boot_us();
>         gd->flags |= GD_FLG_FULL_MALLOC_INIT;
>         return 0;
>  }
> @@ -570,6 +573,8 @@ static int dm_announce(void)
>
>  static int run_main_loop(void)
>  {
> +       printf("malloc_init took %luus (%lu %lu)\n", malloc_end - malloc_begin,
> +              malloc_begin, malloc_end);
>  #ifdef CONFIG_SANDBOX
>         sandbox_main_loop_init();
>  #endif
> diff --git a/common/spl/spl.c b/common/spl/spl.c
> index d74acec10b5..b34d1f4b4e6 100644
> --- a/common/spl/spl.c
> +++ b/common/spl/spl.c
> @@ -755,7 +755,9 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
>         spl_set_bd();
>
>  #if defined(CONFIG_SYS_SPL_MALLOC)
> +       ulong malloc_begin = timer_get_boot_us();
>         mem_malloc_init(SYS_SPL_MALLOC_START, CONFIG_SYS_SPL_MALLOC_SIZE);
> +       ulong malloc_end = timer_get_boot_us();
>         gd->flags |= GD_FLG_FULL_MALLOC_INIT;
>  #endif
>         if (!(gd->flags & GD_FLG_SPL_INIT)) {
> @@ -817,6 +819,8 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
>         spl_image.boot_device = BOOT_DEVICE_NONE;
>         board_boot_order(spl_boot_list);
>
> +       printf("malloc_init took %luus (%lu %lu)\n", malloc_end - malloc_begin,
> +              malloc_begin, malloc_end);

debug() ?

>         ret = boot_from_devices(&spl_image, spl_boot_list,
>                                 ARRAY_SIZE(spl_boot_list));
>         if (ret) {
> --
> 2.25.1
>
> I found that MALLOC_CLEAR_ON_INIT dominated the mem_malloc_init time
> (taking around 150 ms in SPL on my board). After disabling it, I found
> that MALLOC_RUNTIME_INIT took around 5 us on average.
>
> [1] https://lore.kernel.org/u-boot/20230926141514.2101787-1-sjg@chromium.org/
> [2] https://source.denx.de/u-boot/custodians/u-boot-clk/-/pipelines/17900
>
> Changes in v3:
> - Use CONFIG_IS_ENABLED in conditionals
> - Don't enable SPL_SYS_MALLOC_RUNTIME_INIT if we are short on BSS
>
> Changes in v2:
> - Only mark malloc initialized after mem_malloc_init
> - Fix cALLOc condition
>
> Sean Anderson (4):
>   common: Only mark malloc initialized after mem_malloc_init
>   malloc: Don't use ifdefs for SYS_MALLOC_DEFAULT_TO_INIT
>   malloc: Don't statically initialize av_ if using malloc_init
>   malloc: Enable SYS_MALLOC_RUNTIME_INIT by default in SPL
>
>  Kconfig           | 27 +++++++++++++++++----------
>  common/board_r.c  |  3 ++-
>  common/dlmalloc.c | 16 ++++++++--------
>  3 files changed, 27 insertions(+), 19 deletions(-)
>
> --
> 2.35.1.1320.gc452695387.dirty
>

REgards,
SImon