Re: [PATCH 09/15] irq: arm: perform irqentry in entry code
From: Marc Zyngier
Date: Wed Dec 01 2021 - 02:56:55 EST
On 2021-11-30 08:49, Vladimir Murzin wrote:
One month and a week later...
I observe that in terms of performance
MRS r0, ipsr
is equivalent to readl_relaxed(BASEADDR_V7M_SCB + V7M_SCB_ICSR)
MOV.W r3, #3758153728
LDR.W r0, [r3, #3332]
Old compilers can produce less performant sequence like
LDR r3,0xbcc0
ADD.W r3,r3,#0xaf00
LDR r0,[r3,#0]
So, what would be your preference?
If there is no significant overhead to reading the MMIO register
and that you see a benefit in enabling COMPILE_TEST, then this
probably is the way to go.
Thanks,
M.
--
Jazz is not dead. It just smells funny...