Hi Przemyslaw, > For ARM architecture, enable the CONFIG_USE_ARCH_MEMSET/MEMCPY, > will highly increase the memset/memcpy performance. This is able > thanks to the ARM multiple register instructions. > > Unfortunatelly the relocation is done without the cache enabled, > so it takes some time, but zeroing the BSS memory takes much more > longer, especially for the configs with big static buffers. > > A quick test confirms, that the boot time improvement after using > the arch memcpy for relocation has no significant meaning. > The same test confirms that enable the memset for zeroing BSS, > reduces the boot time. > > So this patch enables the arch memset for zeroing the BSS after > the relocation process. For ARM boards, this can be enabled > in board configs by defining: 'CONFIG_USE_ARCH_MEMSET'. > > This was tested on Trats2. > A quick test with trace. Boot time from start to main_loop() entry: > - ~1384ms - before this change > - ~888ms - after this change > > Signed-off-by: Przemyslaw Marczak <[email protected]> > Reviewed-by: Simon Glass <[email protected]> > Cc: Albert Aribaud <[email protected]> > Cc: Tom Rini <[email protected]> > --- > Changes V3, V4, V5 > - none > --- > arch/arm/lib/crt0.S | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S > index 22df3e5..fab3d2c 100644 > --- a/arch/arm/lib/crt0.S > +++ b/arch/arm/lib/crt0.S > @@ -115,14 +115,22 @@ here: > bl c_runtime_cpu_setup /* we still call old > routine here */ > ldr r0, =__bss_start /* this is > auto-relocated! */ > - ldr r1, =__bss_end /* this is > auto-relocated! */ > +#ifdef CONFIG_USE_ARCH_MEMSET > + ldr r3, =__bss_end /* this is > auto-relocated! */ > + mov r1, #0x00000000 /* prepare zero to > clear BSS */ + > + subs r2, r3, r0 /* r2 = memset len */ > + bl memset > +#else > + ldr r1, =__bss_end /* this is > auto-relocated! */ mov r2, #0x00000000 /* > prepare zero to clear BSS */ > clbss_l:cmp r0, r1 /* while not at end > of BSS */ strlo r2, [r0] /* clear 32-bit BSS > word */ addlo r0, r0, #4 /* move to next */ > blo clbss_l > +#endif > > bl coloured_LED_init > bl red_led_on
Acked-by: Lukasz Majewski <[email protected]> -- Best regards, Lukasz Majewski Samsung R&D Institute Poland (SRPOL) | Linux Platform Group _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
