linux-kernel - Re: [PATCH] intel_idle: add CPUIDLE_FLAG_IRQ

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Message-ID: <e0869b55706915821a6aa1ba0140a784d263b01e.camel@linux.intel.com>
Date:   Sun, 12 Nov 2023 13:52:12 +0200
From:   Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
To:     Jon Kohler <jon@...anix.com>
Cc:     Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        Len Brown <lenb@...nel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] intel_idle: add CPUIDLE_FLAG_IRQ_ENABLE to SPR C1 and
 C1E

On Fri, 2023-11-10 at 20:00 +0000, Jon Kohler wrote:
> CPUIDLE_FLAG_IRQ_ENABLE

Hi, yes, I did run several experiments, and found that this change would make
some micro benchmarks give worse score. I did a lot of repetitions assuming I
was mixing noise with signal, but every time confirmed that enabling interrupts
in C1 made the score worse (like 1%).

I do not have explanation for this phenomena, but decided to not pursue this
idea.

Artem.