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? > 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
