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From: Thomas Gleixner <tglx@linutronix.de>
To: Florian Fainelli <f.fainelli@gmail.com>, Florian Fainelli
 <florian.fainelli@broadcom.com>, linux-kernel@vger.kernel.org
Cc: opendmb@gmail.com, Tim Ross <tim.ross@broadcom.com>, Broadcom internal
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Subject: Re: [PATCH] irqchip/irq-brcmstb-l2: Avoid saving mask on shutdown
In-Reply-To: <958c27b1-26d7-4927-976b-4502f33f31f7@gmail.com>
References: <20240416194343.469318-1-florian.fainelli@broadcom.com>
 <87le55ulw5.ffs@tglx> <958c27b1-26d7-4927-976b-4502f33f31f7@gmail.com>
Date: Tue, 23 Apr 2024 01:45:27 +0200
Message-ID: <87il09ufl4.ffs@tglx>
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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 :)