Hi Przemyslaw, > On Jan 28, 2015, at 16:30 , Przemyslaw Marczak <p.marc...@samsung.com> wrote: > > 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. >
How big is this .bss section? We’re talking about something that takes 1.5secs to clear a few MBs of memory? This is horrible. Even at the optimized case .5secs is too much. >>> 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 Regards — Pantelis _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
