[PATCH] lib: sparse: allocate blkcnt instead of arbitrary small number
Mattijs Korpershoek
mkorpershoek at baylibre.com
Fri Jul 7 08:52:50 CEST 2023
On jeu., juil. 06, 2023 at 13:00, Tom Rini <trini at konsulko.com> wrote:
> On Thu, Jul 06, 2023 at 11:43:13AM +0200, Mattijs Korpershoek wrote:
>> On lun., juin 19, 2023 at 10:21, Mattijs Korpershoek <mkorpershoek at baylibre.com> wrote:
>>
>> > Hi Qianfan,
>> >
>> > Thank you for your review.
>> >
>> > On lun., juin 19, 2023 at 14:19, qianfan <qianfanguijin at 163.com> wrote:
>> >
>> >> 在 2023/6/16 21:26, 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 * blkcnt) as suggested in
>> >>> the original's patch review [2].
>> >>>
>> >>> With this patch, performance impact is mitigated:
>> >>> Sending sparse 'super' 1/2 (768793 KB) OKAY [ 24.006s]
>> >>> Writing 'super' OKAY [ 15.920s]
>> >>> Sending sparse 'super' 2/2 (629819 KB) OKAY [ 19.651s]
>> >>> Writing 'super' OKAY [ 14.665s]
>> >>> Finished. Total time: 74.346s
>> >>>
>> >>> [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>
>> >>> ---
>> >>> lib/image-sparse.c | 2 +-
>> >>> 1 file changed, 1 insertion(+), 1 deletion(-)
>> >>>
>> >>> diff --git a/lib/image-sparse.c b/lib/image-sparse.c
>> >>> index 5ec0f94ab3eb..25aed0604192 100644
>> >>> --- a/lib/image-sparse.c
>> >>> +++ b/lib/image-sparse.c
>> >>> @@ -55,7 +55,7 @@ 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, aligned_buf_blks = blkcnt;
>> >> Hi:
>> >>
>> >> It's a good point that this code report the performance was affected by
>> >> write large small
>> >> mmc blks, not memory copy.
>> >
>> > I believe memory copy also affects performance, but in my case,
>> > it has less impact than small mmc blks.
>> >
>> > With 62649165cb02 reverted:
>> > Sending sparse 'super' 1/2 (768793 KB) OKAY [ 23.947s]
>> > Writing 'super' OKAY [ 12.983s]
>> > Sending sparse 'super' 2/2 (629819 KB) OKAY [ 19.600s]
>> > Writing 'super' OKAY [ 12.796s]
>> > Finished. Total time: 69.430s
>> >
>> > With aligned_buf_blks = blkcnt:
>> > Sending sparse 'super' 1/2 (768793 KB) OKAY [ 24.072s]
>> > Writing 'super' OKAY [ 16.177s]
>> > Sending sparse 'super' 2/2 (629819 KB) OKAY [ 19.681s]
>> > Writing 'super' OKAY [ 14.845s]
>> > Finished. Total time: 74.919s
>> >
>> >>
>> >> And I can not make sure whether memalign can always alloc such huge
>> >> memory when we change the
>> >> aligned_buf_blks to blkcnt.
>> >
>> > Could you clarify the concern here? I've dumped blkcnt for my board
>> > (AM62x SK EVK) and the biggest blkcnt I found was: 131072
>> >
>> > With info->blksz = 512, this gives me: 512 * 131072 = 67108864
>> >
>> > Which is a memalign (memory alloc) of 64MB. Is 64MB really that big? (I
>> > don't realize it's that much)
>> >
>> >>
>> >> Could you please set aligned_buf_blks to FASTBOOT_MAX_BLK_WRITE(16384)
>> >> and test again?
>> >
>> > With aligned_buf_blks = FASTBOOT_MAX_BLK_WRITE(16384):
>> > 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
>> >
>> > So using FASTBOOT_MAX_BLK_WRITE is slightly worse than using blkcnt.
>> > But allocations (for blksz = 512) are smaller: 8MB instead of 64MB in my example.
>> >
>> > I can spin up a v2 with FASTBOOT_MAX_BLK_WRITE but i'm waiting a little
>> > more feedback before doing so.
>>
>> Hi Marek, Tom,
>>
>> What's your take on this ? Can we keep blkcnt or should I respin using
>> FASTBOOT_MAX_BLK_WRITE ?
>>
>> I have also tested this on VIM3, on
>> U-Boot 2023.07-rc6-00003-g923de765ee1a:
>>
>> Sending sparse 'super' 1/13 (114684 KB) OKAY [ 5.442s]
>> Writing 'super' OKAY [ 5.791s]
>> Sending sparse 'super' 2/13 (114684 KB) OKAY [ 5.706s]
>> Writing 'super' OKAY [ 5.607s]
>> Sending sparse 'super' 3/13 (114684 KB) OKAY [ 5.468s]
>> Writing 'super' OKAY [ 5.835s]
>> Sending sparse 'super' 4/13 (114684 KB) OKAY [ 5.703s]
>> Writing 'super' OKAY [ 5.618s]
>> Sending sparse 'super' 5/13 (114684 KB) OKAY [ 6.176s]
>> Writing 'super' OKAY [ 5.421s]
>> Sending sparse 'super' 6/13 (104176 KB) OKAY [ 5.204s]
>> Writing 'super' OKAY [ 5.199s]
>> Sending sparse 'super' 7/13 (108856 KB) OKAY [ 5.456s]
>> Writing 'super' OKAY [ 5.290s]
>> Sending sparse 'super' 8/13 (114684 KB) OKAY [ 6.122s]
>> Writing 'super' OKAY [ 5.838s]
>> Sending sparse 'super' 9/13 (114684 KB) OKAY [ 5.951s]
>> Writing 'super' OKAY [ 5.857s]
>> Sending sparse 'super' 10/13 (100980 KB) OKAY [ 4.902s]
>> Writing 'super' OKAY [ 4.749s]
>> Sending sparse 'super' 11/13 (114681 KB) OKAY [ 6.041s]
>> Writing 'super' OKAY [ 5.779s]
>> Sending sparse 'super' 12/13 (107212 KB) OKAY [ 5.174s]
>> Writing 'super' OKAY [ 6.587s]
>> Sending sparse 'super' 13/13 (71496 KB) OKAY [ 3.717s]
>> Writing 'super' OKAY [ 3.744s]
>> Finished. Total time: 142.578s
>>
>> With this patch:
>> Sending sparse 'super' 1/13 (114684 KB) OKAY [ 7.149s]
>> Writing 'super' OKAY [ 1.639s]
>> Sending sparse 'super' 2/13 (114684 KB) OKAY [ 6.993s]
>> Writing 'super' OKAY [ 1.713s]
>> Sending sparse 'super' 3/13 (114684 KB) OKAY [ 7.029s]
>> Writing 'super' OKAY [ 1.107s]
>> Sending sparse 'super' 4/13 (114684 KB) OKAY [ 7.027s]
>> Writing 'super' OKAY [ 0.162s]
>> Sending sparse 'super' 5/13 (114684 KB) OKAY [ 6.930s]
>> Writing 'super' OKAY [ 1.643s]
>> Sending sparse 'super' 6/13 (104176 KB) OKAY [ 6.253s]
>> Writing 'super' OKAY [ 2.348s]
>> Sending sparse 'super' 7/13 (108856 KB) OKAY [ 6.346s]
>> Writing 'super' OKAY [ 0.723s]
>> Sending sparse 'super' 8/13 (114684 KB) OKAY [ 6.715s]
>> Writing 'super' OKAY [ 2.848s]
>> Sending sparse 'super' 9/13 (114684 KB) OKAY [ 6.888s]
>> Writing 'super' OKAY [ 1.928s]
>> Sending sparse 'super' 10/13 (100980 KB) OKAY [ 5.979s]
>> Writing 'super' OKAY [ 1.178s]
>> Sending sparse 'super' 11/13 (114681 KB) OKAY [ 6.822s]
>> Writing 'super' OKAY [ 2.652s]
>> Sending sparse 'super' 12/13 (107212 KB) OKAY [ 6.414s]
>> Writing 'super' OKAY [ 5.109s]
>> Sending sparse 'super' 13/13 (71496 KB) OKAY [ 4.238s]
>> Writing 'super' OKAY [ 0.252s]
>> Finished. Total time: 108.151s
>>
>> It's probably too late for v2023.07 to pick this up but can we consider
>> taking it for next?
>
> I was waiting for a v2, and yes, it's too late for v2023.07. Sorry for
> not being clear enough.
Oh, sorry I did not understand that. I understand for v2023.07.
Thank you for the quick answer.
Will send a v2 shortly using FASTBOOT_MAX_BLK_WRITE.
>
> --
> Tom
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