Hello,
On 01/28/2015 03:18 PM, Pantelis Antoniou wrote:
Hi Przemyslaw,
On Jan 28, 2015, at 16:10 , Przemyslaw Marczak <p.marc...@samsung.com> wrote:
Hello Stefan,
On 01/28/2015 02:12 PM, Stefan Roese wrote:
Hi Przemyslaw,
On 28.01.2015 13:55, Przemyslaw Marczak wrote:
This patchset reduces the boot time for ARM architecture,
Exynos boards, and boards with DFU enabled(ARM).
For tested Trats2 device, this was done in three steps.
First was enable the arch memcpy and memset.
The second step was enable memset for .bss clear.
The third step for reduce this operation is to keep .bss section
small as possible.
The .bss section will grow if we have a lot of static variables.
This section is cleared before jump to the relocated U-Boot,
and it's done word by word. To reduce the time for this step,
we can enable arch memset, which uses multiple ARM registers.
For configs with DFU enabled, we can find the dfu buffer in this section,
which has at least 8MB (32MB for trats2). This is a lot of useless data,
which is not required for standard boot. So this buffer should be dynamic
allocated.
Przemyslaw Marczak (3):
exynos: config: enable arch memcpy and arch memset
arm: relocation: clear .bss section with arch memset if defined
dfu: mmc: file buffer: remove static allocation
arch/arm/lib/crt0.S | 10 +++++++++-
drivers/dfu/dfu_mmc.c | 25 ++++++++++++++++++++++---
include/configs/exynos-common.h | 3 +++
3 files changed, 34 insertions(+), 4 deletions(-)
Looking at the commit messages of this patchset I can conclude that your
overall boot time reduction is:
from ~1527ms
to ~464ms
This is amazing! Congrats. :)
Thank you. I was also amazed.
The time results are taken with from the clock cycle counter, I think it's
reliable. Some day I would like to check it using the oscilloscope.
We really should in general make more use of the optimized functions and
take care that the buffers (e.g. the DFU buffer in this case) are used
in a sane way.
Thanks,
Stefan
Yes you're right, I thought that Exynos config has enabled arch memcpy/set lib,
before I checked this…
Those numbers are indeed incredible; I suppose the caches are disabled?
The caches are enabled after the relocation, in one of board_init_r calls.
Best regards,
--
Przemyslaw Marczak
Samsung R&D Institute Poland
Samsung Electronics
p.marc...@samsung.com
Regards
— Pantelis
Best regards,
--
Przemyslaw Marczak
Samsung R&D Institute Poland
Samsung Electronics
p.marc...@samsung.com
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