[PATCH 3/3] malloc: Enable SYS_MALLOC_RUNTIME_INIT by default in SPL

[Sean Anderson]

On 8/1/23 11:25, Tom Rini wrote:
> On Mon, Jul 31, 2023 at 06:33:27PM -0400, Sean Anderson wrote:
> 
>> On boards with size restrictions, 1-2k can be a significant fraction of
>> the binary size. Add a new SPL version of SYS_MALLOC_RUNTIME_INIT and
>> enable it by default.
>> 
>> Signed-off-by: Sean Anderson <sean.anderson at seco.com>
>> ---
>> 
>>  Kconfig | 11 +++++++++++
>>  1 file changed, 11 insertions(+)
>> 
>> diff --git a/Kconfig b/Kconfig
>> index 4b32286b69..3cb31a9346 100644
>> --- a/Kconfig
>> +++ b/Kconfig
>> @@ -381,6 +381,17 @@ config SYS_MALLOC_RUNTIME_INIT
>>           reduce the size of U-Boot by letting malloc's data reside in .bss
>>           instead of .data.
>>  
>> +config SPL_SYS_MALLOC_RUNTIME_INIT
>> +	bool "Initialize malloc's internal data at runtime in SPL"
>> +	default y
>> +	depends on SPL
>> +	help
>> +	 Initialize malloc's internal data structures at SPL runtime, rather
>> +	 than at compile-time. This is necessary if relocating the malloc arena
>> +	 from a smaller static memory to a large DDR memory. It can also reduce
>> +	 the size of U-Boot by letting malloc's data reside in .bss instead of
>> +	 .data.
>> +
>>  config TOOLS_DEBUG
>>  	bool "Enable debug information for tools"
>>  	help
> 
> Can you use something like grabserial (or other tooling) to quantify the
> change on a platform or two?

I had a ZynqMP board roughly based on xilinx_zynqmp_virt_defconfig lying
around. On this board, serial is not initialized until after malloc, so
I used the internal timer and printed the times later. DEBUG_UART would
probably be better but I didn't get it working.

diff --git a/common/board_r.c b/common/board_r.c
index d798c00a80a..d7aee85e5b1 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();
        mem_malloc_init((ulong)map_sysmem(malloc_start, TOTAL_MALLOC_LEN),
                        TOTAL_MALLOC_LEN);
+       malloc_end = timer_get_boot_us();
        return 0;
 }
 
@@ -569,6 +572,7 @@ 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..09abcc74442 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 +819,7 @@ 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);
        ret = boot_from_devices(&spl_image, spl_boot_list,
                                ARRAY_SIZE(spl_boot_list));
        if (ret) {

I recorded times (in us) from five boots. The value of
(SPL_)SYS_MALLOC_RUNTIME_INIT is in parentheses:

SPL (n) U-Boot (n) SPL (y) U-Boot (y)
======= ========== ======= ==========
192975       47557  135027      47557
192940       47557  135059      47557
193006       47557  134722      47558
193015       47556  135055      47557
193987       47557  134790      47557
             
So SPL took 60 ms shorter (?!) and U-Boot was mostly unaffected. Not
sure how that happened. The raw values for begin/end look reasonable:

  malloc_init took 47557us (6778108 6825665)
  malloc_init took 47557us (6779290 6826847)
  malloc_init took 47558us (6780379 6827937)

etc. but to be honest I don't really see how SPL can spend 190ms setting
some variables and clearing the arena.

--Sean