[PATCH v2] lib: sparse: allocate FASTBOOT_MAX_BLK_WRITE instead of small number

[qianfan]

在 2023/7/7 16:13, Mattijs Korpershoek 写道:
> Commit 62649165cb02 ("lib: sparse: Make CHUNK_TYPE_RAW buffer aligned")
> fixed cache alignment for systems with a D-CACHE.
>
> However it introduced some performance regressions [1] on system
> flashing huge images, such as Android.
>
> On AM62x SK EVM, we also observe such performance penalty:
> Sending sparse 'super' 1/2 (768793 KB)             OKAY [ 23.954s]
> Writing 'super'                                    OKAY [ 75.926s]
> Sending sparse 'super' 2/2 (629819 KB)             OKAY [ 19.641s]
> Writing 'super'                                    OKAY [ 62.849s]
> Finished. Total time: 182.474s
>
> The reason for this is that we use an arbitrary small buffer
> (info->blksz * 100) for transferring.
>
> Fix it by using a bigger buffer (info->blksz * FASTBOOT_MAX_BLK_WRITE)
> as suggested in the original's patch review [2].
>
> With this patch, performance impact is mitigated:
> Sending sparse 'super' 1/2 (768793 KB)             OKAY [ 23.912s]
> Writing 'super'                                    OKAY [ 15.780s]
> Sending sparse 'super' 2/2 (629819 KB)             OKAY [ 19.581s]
> Writing 'super'                                    OKAY [ 17.192s]
> Finished. Total time: 76.569s
>
> [1] https://lore.kernel.org/r/20221118121323.4009193-1-gary.bisson@boundarydevices.com
> [2] https://lore.kernel.org/r/all/43e4c17c-4483-ec8e-f843-9b4c5569bd18@seco.com/
>
> Fixes: 62649165cb02 ("lib: sparse: Make CHUNK_TYPE_RAW buffer aligned")
> Signed-off-by: Mattijs Korpershoek <mkorpershoek at baylibre.com>
> ---
> Changes in v2:
> - Use FASTBOOT_MAX_BLK_WRITE instead of blkcnt (Qianfan)
> - Link to v1: https://lore.kernel.org/r/20230616-sparse-flash-fix-v1-1-6bafeacc567b@baylibre.com
> ---
>   drivers/fastboot/fb_mmc.c | 2 --
>   include/image-sparse.h    | 2 ++
>   lib/image-sparse.c        | 3 ++-
>   3 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/fastboot/fb_mmc.c b/drivers/fastboot/fb_mmc.c
> index 9d25c402028a..060918e49109 100644
> --- a/drivers/fastboot/fb_mmc.c
> +++ b/drivers/fastboot/fb_mmc.c
> @@ -19,8 +19,6 @@
>   #include <linux/compat.h>
>   #include <android_image.h>
>   
> -#define FASTBOOT_MAX_BLK_WRITE 16384
> -
>   #define BOOT_PARTITION_NAME "boot"
>   
>   struct fb_mmc_sparse {
> diff --git a/include/image-sparse.h b/include/image-sparse.h
> index 0572dbd0a283..282a0b256498 100644
> --- a/include/image-sparse.h
> +++ b/include/image-sparse.h
> @@ -7,6 +7,8 @@
>   #include <part.h>
>   #include <sparse_format.h>
>   
> +#define FASTBOOT_MAX_BLK_WRITE 16384
Hi:

Just a personal suggestion, define sometings like FASTBOOT_MAX_BLK_WRITE in
image-sparse.c is very strange.

Or maybe define a marco such as SPARSE_MAX_BLK_WRITE and set a default
value to 16384, and leave some comments for why we choice this value.

Thanks.
> +
>   #define ROUNDUP(x, y)	(((x) + ((y) - 1)) & ~((y) - 1))
>   
>   struct sparse_storage {
> diff --git a/lib/image-sparse.c b/lib/image-sparse.c
> index 5ec0f94ab3eb..8f8a67e15804 100644
> --- a/lib/image-sparse.c
> +++ b/lib/image-sparse.c
> @@ -55,7 +55,8 @@ static lbaint_t write_sparse_chunk_raw(struct sparse_storage *info,
>   				       void *data,
>   				       char *response)
>   {
> -	lbaint_t n = blkcnt, write_blks, blks = 0, aligned_buf_blks = 100;
> +	lbaint_t n = blkcnt, write_blks, blks = 0;
> +	lbaint_t aligned_buf_blks = FASTBOOT_MAX_BLK_WRITE;
>   	uint32_t *aligned_buf = NULL;
>   
>   	if (CONFIG_IS_ENABLED(SYS_DCACHE_OFF)) {
>
> ---
> base-commit: 923de765ee1a5b26310f02cb42dcbad9e2b011c5
> change-id: 20230616-sparse-flash-fix-9c2852aa8d16
>
> Best regards,