[PATCH] lib: sparse: allocate blkcnt instead of arbitrary small number
Tom Rini
trini at konsulko.com
Thu Jul 6 19:00:40 CEST 2023
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.
--
Tom
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