From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Lendacky, Thomas" <Thomas.Lendacky@amd.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
Jerry Hoemann <jerry.hoemann@hpe.com>
Subject: Re: [PATCH] perf/x86/amd: Change NMI latency mitigation to use a timestamp
Date: Thu, 1 Aug 2019 23:59:45 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1908012352390.1789@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190801214813.GB2332@hirez.programming.kicks-ass.net>
On Thu, 1 Aug 2019, Peter Zijlstra wrote:
> On Thu, Aug 01, 2019 at 11:34:23PM +0200, Thomas Gleixner wrote:
> > Avoid the whole NMI mess, make the PMC interrupt a proper vector in the
> > highest prio bucket and instead of using CLI/STI use CR8. That would have
> > the additional advantage that we could prevent perf "NMI" then occsionally :)
>
> Exactly, and not only the PMC, we can basically start giving out actual
> vectors on register_nmi_handler() and do away with all that shared line
> crap.
>
> And then the actual NMI line will be mostly empty again, and it can read
> its stupid slow reason port again.
>
> One complication though; IRET et al only do EFLAGS, not CR8, so that's
> going to be massive fun :-(
>
> Did I say I hates the x86 interrupt scheme?
You're not alone.
That stuff definitely violates article 3 of the Convention for the
Protection of Human Rights and Fundamental Freedoms.
next prev parent reply other threads:[~2019-08-01 21:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 18:57 Lendacky, Thomas
2019-08-01 21:16 ` Peter Zijlstra
2019-08-01 21:29 ` Lendacky, Thomas
2019-08-01 21:34 ` Thomas Gleixner
2019-08-01 21:48 ` Peter Zijlstra
2019-08-01 21:59 ` Thomas Gleixner [this message]
2019-08-02 14:33 ` Lendacky, Thomas
2019-08-02 16:20 ` Peter Zijlstra
2019-08-02 16:33 ` Peter Zijlstra
2019-08-08 20:33 ` Jerry Hoemann
2019-09-13 19:52 ` Jerry Hoemann
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