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Date:   Mon, 26 Feb 2018 12:39:37 -0800
From:   Andi Kleen <ak@linux.intel.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Cong Wang <xiyou.wangcong@gmail.com>,
        "Liang, Kan" <kan.liang@intel.com>, jolsa@redhat.com,
        bigeasy@linutronix.de, "H. Peter Anvin" <hpa@zytor.com>,
        Ingo Molnar <mingo@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>, x86 <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: Long standing kernel warning: perfevents: irq loop stuck!
Message-ID: <20180226203937.GA21543@tassilo.jf.intel.com>
References: <CAM_iQpXvuYKn94WjJ9nSjzhk8DzYAvDmdgxsi6cc9CdBfkdTnw@mail.gmail.com>
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> Given the HSD143 errata and its possible relevance, have you tried
> changing the magic number to 32, does it then still fix things?
> 
> No real objection to the patch as such, it just needs a coherent comment
> and a tested-by tag I think.

128 min period will affect a lot of valid use cases with slower ticking
events.  I often use smaller periods there.

It would be better to debug this properly.

Or at a minimum only do the limitation for the events that tick really
fast (like cycles, uops retired etc.)

-Andi