linux-kernel - Re: [PATCH] irqchip/irq-brcmstb-l2: Avoid saving mask on shutdown

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Message-ID: <f98dffd7-bb1c-4023-9a73-fdf2107160d1@gmail.com>
Date: Wed, 24 Apr 2024 09:50:40 -0700
From: Florian Fainelli <f.fainelli@...il.com>
To: Thomas Gleixner <tglx@...utronix.de>,
 Florian Fainelli <florian.fainelli@...adcom.com>,
 linux-kernel@...r.kernel.org
Cc: opendmb@...il.com, Tim Ross <tim.ross@...adcom.com>,
 Broadcom internal kernel review list
 <bcm-kernel-feedback-list@...adcom.com>,
 "open list:BROADCOM BMIPS MIPS ARCHITECTURE" <linux-mips@...r.kernel.org>,
 "moderated list:BROADCOM BCM7XXX ARM ARCHITECTURE"
 <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] irqchip/irq-brcmstb-l2: Avoid saving mask on shutdown

On 4/22/24 16:45, Thomas Gleixner wrote:
> On Mon, Apr 22 2024 at 15:26, Florian Fainelli wrote:
>> On 4/22/24 14:29, Thomas Gleixner wrote:
>>>> +	if (save)
>>>> +		b->saved_mask = irq_reg_readl(gc, ct->regs.mask);
>>>
>>> what's the conditional actually buying you except more complex code?
>>
>> Not much this is an optimization that is simple to carry out. There can
>> be dozens of such L2 interrupt controllers in a given system and the
>> MMIO accesses start adding up eventually.
> 
> I'm impressed by saving ~12 microseconds per one dozen of interrupt
> controllers on system shutdown :)

I know, right? More seriously are you willing to take that patch, should 
I write a better justification?
-- 
Florian