From: Giovanni Gherdovich <ggherdovich@suse.cz>
To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@suse.de>,
Len Brown <lenb@kernel.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
x86@kernel.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 1/2] x86, sched: Prevent divisions by zero in frequency invariant accounting
Date: Tue, 19 May 2020 18:46:47 +0200 [thread overview]
Message-ID: <1589906807.13984.22.camel@suse.cz> (raw)
In-Reply-To: <20200518222037.GA14829@ranerica-svr.sc.intel.com>
On Mon, 2020-05-18 at 15:20 -0700, Ricardo Neri wrote:
> On Sat, May 02, 2020 at 04:25:00PM +0200, Giovanni Gherdovich wrote:
> > >
> > > I've changed the patch like so.. OK?
> > >
> > > (ok, perhaps I went a little overboard with the paranoia ;-)
> >
> > Right, I wasn't really checking for overflow, only for when the product
> > "mcnt * arch_max_freq_ratio" becomes zero.
> >
> > Thanks for your edit (I took note of the macros check_*_overflow, didn't know
> > them). I fully subscribe to the paranoid approach.
> >
> > I understand you've already edited the patches in your tree, so I am not
> > resending, just confirming my
> >
> > Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
>
> Hi, have these changes been merged? I still don't see them in the tip or
> Linus' tree.
>
Hi Ricardo,
the kbuild bot found an error in this patch, the macro check_mul_overflow
doesn't build on x86 32bit, so Peter Zijlstra hasn't merged it yet.
This is the error:
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org/thread/7GDIBOMNVDG5W2XZD4EICE2TUZR3THBN/
I'm writing a patch to avoid doing frequency invariance entirely on i386.
I doubt those machines have APERFMPERF anyways. This will fix the build error.
Cheers,
Giovanni
next prev parent reply other threads:[~2020-05-19 16:46 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 13:24 [PATCH 0/2] More frequency invariance fixes for x86 Giovanni Gherdovich
2020-04-28 13:24 ` [PATCH 1/2] x86, sched: Prevent divisions by zero in frequency invariant accounting Giovanni Gherdovich
2020-04-29 11:30 ` Rafael J. Wysocki
2020-05-01 13:30 ` Peter Zijlstra
2020-05-02 14:25 ` Giovanni Gherdovich
2020-05-18 22:20 ` Ricardo Neri
2020-05-19 16:46 ` Giovanni Gherdovich [this message]
2020-04-28 13:24 ` [PATCH 2/2] x86, sched: Bail out of frequency invariance if turbo frequency is unknown Giovanni Gherdovich
2020-04-29 11:30 ` Rafael J. Wysocki
2020-05-01 13:04 ` Peter Zijlstra
2020-05-02 0:06 ` Ricardo Neri
2020-05-02 14:26 ` Giovanni Gherdovich
2020-05-02 0:04 ` Ricardo Neri
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