From: Andi Kleen <ak@linux.intel.com>
To: speck@linutronix.de
Subject: [MODERATED] Re: [RFC][PATCH] performance walnuts
Date: Fri, 8 Feb 2019 20:34:06 -0800 [thread overview]
Message-ID: <20190209043406.GD16922@tassilo.jf.intel.com> (raw)
In-Reply-To: <CAHk-=wj9GxpNNAJHoFGPda7LR=niSx38TGeArx6KNJHH+N7pDw@mail.gmail.com>
On Fri, Feb 08, 2019 at 04:28:41PM -0800, speck for Linus Torvalds wrote:
> On Fri, Feb 8, 2019 at 2:53 AM speck for Peter Zijlstra
> <speck@linutronix.de> wrote:
> >
> > +static void intel_set_tfa(struct cpu_hw_events *cpuc, bool on)
> > +{
> > + u64 val = MSR_TFA_RTM_FORCE_ABORT * on;
>
> Have you actually verified that this does the right thing on all
> versions of gcc?
>
> In particular, I certainly hope it doesn't cause an actual multiply instruction.
On Skylake IMUL is 3 cycles latency so it should be fine in any case.
-Andi
next prev parent reply other threads:[~2019-02-09 4:34 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-07 23:41 [MODERATED] [PATCH v3 0/6] PERFv3 Andi Kleen
2019-02-07 23:41 ` [MODERATED] [PATCH v3 1/6] PERFv3 Andi Kleen
2019-02-08 8:45 ` [MODERATED] " Peter Zijlstra
2019-02-07 23:41 ` [MODERATED] [PATCH v3 2/6] PERFv3 Andi Kleen
2019-02-08 0:51 ` [MODERATED] Re: [SUSPECTED SPAM][PATCH " Andrew Cooper
2019-02-08 9:01 ` Peter Zijlstra
2019-02-08 9:31 ` [MODERATED] Re: [PATCH " Andrew Cooper
2019-02-08 9:39 ` [MODERATED] Re: [SUSPECTED SPAM][PATCH " Peter Zijlstra
2019-02-08 10:53 ` [MODERATED] [RFC][PATCH] performance walnuts Peter Zijlstra
2019-02-08 18:07 ` [MODERATED] " Andi Kleen
2019-02-11 10:40 ` Peter Zijlstra
2019-02-11 14:06 ` Thomas Gleixner
2019-02-11 20:17 ` [MODERATED] " Konrad Rzeszutek Wilk
2019-02-11 23:39 ` Thomas Gleixner
2019-02-09 0:28 ` [MODERATED] " Linus Torvalds
2019-02-09 4:34 ` Andi Kleen [this message]
2019-02-09 8:57 ` Peter Zijlstra
2019-02-13 2:56 ` mark gross
2019-02-15 17:32 ` mark gross
2019-02-15 17:44 ` Peter Zijlstra
2019-02-15 20:47 ` mark gross
2019-02-15 21:33 ` Thomas Gleixner
2019-02-19 13:35 ` [MODERATED] [RFC][PATCH v2] " Peter Zijlstra
2019-02-15 23:45 ` [MODERATED] Encrypted Message Jon Masters
2019-02-08 8:50 ` [MODERATED] Re: [PATCH v3 2/6] PERFv3 Peter Zijlstra
2019-02-08 17:26 ` Andi Kleen
2019-02-07 23:41 ` [MODERATED] [PATCH v3 3/6] PERFv3 Andi Kleen
2019-02-08 9:02 ` [MODERATED] " Peter Zijlstra
2019-02-07 23:41 ` [MODERATED] [PATCH v3 4/6] PERFv3 Andi Kleen
2019-02-07 23:41 ` [MODERATED] [PATCH v3 5/6] PERFv3 Andi Kleen
2019-02-08 0:54 ` [MODERATED] " Andrew Cooper
2019-02-07 23:41 ` [MODERATED] [PATCH v3 6/6] PERFv3 Andi Kleen
2019-02-08 9:07 ` [MODERATED] " Peter Zijlstra
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