From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@suse.de>,
Ashok Raj <ashok.raj@intel.com>,
Andi Kleen <andi.kleen@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Ricardo Neri <ricardo.neri@intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Tony Luck <tony.luck@intel.com>,
Clemens Ladisch <clemens@ladisch.de>,
Arnd Bergmann <arnd@arndb.de>,
Philippe Ombredanne <pombredanne@nexb.com>,
Kate Stewart <kstewart@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [RFC PATCH v2 03/14] x86/hpet: Calculate ticks-per-second in a separate function
Date: Mon, 8 Apr 2019 19:04:05 -0700 [thread overview]
Message-ID: <20190409020405.GA7070@ranerica-svr.sc.intel.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1903262201140.1789@nanos.tec.linutronix.de>
On Tue, Mar 26, 2019 at 10:03:02PM +0100, Thomas Gleixner wrote:
> On Wed, 27 Feb 2019, Ricardo Neri wrote:
> > int hpet_alloc(struct hpet_data *hdp)
> > {
> > u64 cap, mcfg;
> > @@ -845,7 +868,6 @@ int hpet_alloc(struct hpet_data *hdp)
> > size_t siz;
> > struct hpet __iomem *hpet;
> > static struct hpets *last;
> > - unsigned long period;
> > unsigned long long temp;
> > u32 remainder;
> >
> > @@ -881,6 +903,8 @@ int hpet_alloc(struct hpet_data *hdp)
> >
> > cap = readq(&hpet->hpet_cap);
> >
> > + temp = hpet_get_ticks_per_sec(cap);
>
> Just putting stuff to random places does not make the code any better.
This seems to not be needed. I'll remove it and directly save the result
in hpetp->hp_tick_freq;
>
> > ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
> >
> > if (hpetp->hp_ntimer != ntimer) {
> > @@ -897,11 +921,6 @@ int hpet_alloc(struct hpet_data *hdp)
> >
> > last = hpetp;
> >
> > - period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
> > - HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
> > - temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
> > - temp += period >> 1; /* round */
> > - do_div(temp, period);
> > hpetp->hp_tick_freq = temp; /* ticks per second */
>
> What's wrong with the obvious:
>
> hpetp->hp_tick_freq = hpet_get_ticks_per_sec(cap);
>
> Hmm?
Nothing wrong. I'll implement this change.
Thanks and BR,
Ricardo
next prev parent reply other threads:[~2019-04-09 2:05 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-27 16:05 [RFC PATCH v2 00/14] Implement an HPET-based hardlockup detector Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 01/14] x86/msi: Add definition for NMI delivery mode Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 02/14] x86/hpet: Expose more functions to read and write registers Ricardo Neri
2019-03-26 21:00 ` Thomas Gleixner
2019-04-09 2:03 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 03/14] x86/hpet: Calculate ticks-per-second in a separate function Ricardo Neri
2019-03-26 21:03 ` Thomas Gleixner
2019-04-09 2:04 ` Ricardo Neri [this message]
2019-02-27 16:05 ` [RFC PATCH v2 04/14] x86/hpet: Reserve timer for the HPET hardlockup detector Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 05/14] x86/hpet: Relocate flag definitions to a header file Ricardo Neri
2019-03-26 21:11 ` Thomas Gleixner
2019-04-09 2:04 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 06/14] x86/hpet: Configure the timer used by the hardlockup detector Ricardo Neri
2019-03-26 21:13 ` Thomas Gleixner
2019-04-09 2:04 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 07/14] watchdog/hardlockup: Define a generic function to detect hardlockups Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 08/14] watchdog/hardlockup: Decouple the hardlockup detector from perf Ricardo Neri
2019-03-26 21:18 ` Thomas Gleixner
2019-04-09 2:05 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 09/14] watchdog/hardlockup: Make arch_touch_nmi_watchdog() to hpet-based implementation Ricardo Neri
2019-02-27 16:17 ` Paul E. McKenney
2019-03-01 1:17 ` Ricardo Neri
2019-03-26 21:20 ` Thomas Gleixner
2019-04-09 2:05 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 10/14] kernel/watchdog: Add a function to obtain the watchdog_allowed_mask Ricardo Neri
2019-03-26 21:22 ` Thomas Gleixner
2019-04-09 2:05 ` Ricardo Neri
2019-04-09 11:34 ` Peter Zijlstra
2019-04-11 1:15 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 11/14] x86/watchdog/hardlockup: Add an HPET-based hardlockup detector Ricardo Neri
2019-03-26 20:49 ` Thomas Gleixner
2019-04-09 2:02 ` Ricardo Neri
2019-04-09 10:59 ` Peter Zijlstra
2019-04-10 1:13 ` Ricardo Neri
2019-04-05 16:12 ` Suthikulpanit, Suravee
2019-04-09 2:14 ` Ricardo Neri
2019-04-09 11:03 ` Peter Zijlstra
2019-04-10 1:05 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 12/14] x86/watchdog/hardlockup/hpet: Determine if HPET timer caused NMI Ricardo Neri
2019-03-26 20:55 ` Thomas Gleixner
2019-04-09 2:02 ` Ricardo Neri
2019-04-09 11:28 ` Peter Zijlstra
2019-04-10 1:19 ` Ricardo Neri
2019-04-10 7:01 ` Peter Zijlstra
2019-04-11 1:12 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 13/14] watchdog/hardlockup/hpet: Only enable the HPET watchdog via a boot parameter Ricardo Neri
2019-03-26 21:29 ` Thomas Gleixner
2019-04-09 2:07 ` Ricardo Neri
2019-02-27 16:05 ` [RFC PATCH v2 14/14] x86/watchdog: Add a shim hardlockup detector Ricardo Neri
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190409020405.GA7070@ranerica-svr.sc.intel.com \
--to=ricardo.neri-calderon@linux.intel.com \
--cc=andi.kleen@intel.com \
--cc=arnd@arndb.de \
--cc=ashok.raj@intel.com \
--cc=bp@suse.de \
--cc=clemens@ladisch.de \
--cc=hpa@zytor.com \
--cc=kstewart@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=pombredanne@nexb.com \
--cc=rafael.j.wysocki@intel.com \
--cc=ravi.v.shankar@intel.com \
--cc=ricardo.neri@intel.com \
--cc=tglx@linutronix.de \
--cc=tony.luck@intel.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®