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From: Chris Metcalf <cmetcalf@mellanox.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	John Stultz <john.stultz@linaro.org>,
	Ingo Molnar <mingo@kernel.org>,
	David Gibson <david@gibson.dropbear.id.au>,
	Liav Rehana <liavr@mellanox.com>,
	Richard Cochran <richardcochran@gmail.com>,
	Parit Bhargava <prarit@redhat.com>,
	Laurent Vivier <lvivier@redhat.com>,
	"Christopher S. Hall" <christopher.s.hall@intel.com>
Subject: Re: [patch 5/6] [RFD] timekeeping: Provide optional 128bit math
Date: Fri, 9 Dec 2016 12:20:52 -0500	[thread overview]
Message-ID: <3f7101ba-5693-c98b-b319-9bab81b151fc@mellanox.com> (raw)
In-Reply-To: <20161209101800.GT3174@twins.programming.kicks-ass.net>

On 12/9/2016 5:18 AM, Peter Zijlstra wrote:
> On Fri, Dec 09, 2016 at 07:38:47AM +0100, Peter Zijlstra wrote:
>
>> Turns out using GCC-6.2.1 we have the same problem on i386, GCC doesn't
>> recognise the 32x32 mults and generates crap.
>>
>> This used to work :/
> I tried:
>
> gcc-4.4: good
> gcc-4.6, gcc-4.8, gcc-5.4, gcc-6.2: bad

I also found 4.4 was good on tilegx at recognizing the 32x32, and bad on
the later versions I tested; I don't recall which specific later versions I
tried, though.

-- 
Chris Metcalf, Mellanox Technologies
http://www.mellanox.com

  reply	other threads:[~2016-12-09 17:37 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-08 20:49 [patch 0/6] timekeeping: Cure the signed/unsigned wreckage Thomas Gleixner
2016-12-08 20:49 ` [patch 1/6] timekeeping: Force unsigned clocksource to nanoseconds conversion Thomas Gleixner
2016-12-08 23:38   ` David Gibson
2016-12-09 11:13   ` [tip:timers/core] timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversion tip-bot for Thomas Gleixner
2016-12-08 20:49 ` [patch 2/6] timekeeping: Make the conversion call chain consistently unsigned Thomas Gleixner
2016-12-08 23:39   ` David Gibson
2016-12-09 11:13   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2016-12-08 20:49 ` [patch 3/6] timekeeping: Get rid of pointless typecasts Thomas Gleixner
2016-12-08 23:40   ` David Gibson
2016-12-09 11:14   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2016-12-08 20:49 ` [patch 4/6] timekeeping: Use mul_u64_u32_shr() instead of open coding it Thomas Gleixner
2016-12-08 23:41   ` David Gibson
2016-12-09 11:14   ` [tip:timers/core] " tip-bot for Thomas Gleixner
2016-12-08 20:49 ` [patch 5/6] [RFD] timekeeping: Provide optional 128bit math Thomas Gleixner
2016-12-09  4:08   ` Ingo Molnar
2016-12-09  4:29     ` Ingo Molnar
2016-12-09  4:39       ` John Stultz
2016-12-09  4:48     ` Peter Zijlstra
2016-12-09  5:22       ` Ingo Molnar
2016-12-09  5:41         ` Peter Zijlstra
2016-12-09  5:11   ` Peter Zijlstra
2016-12-09  6:08     ` Peter Zijlstra
2016-12-09  5:26   ` Peter Zijlstra
2016-12-09  6:38     ` Peter Zijlstra
2016-12-09  8:30       ` Peter Zijlstra
2016-12-09  9:11         ` Peter Zijlstra
2016-12-09 10:01         ` Peter Zijlstra
2016-12-09 17:32         ` Chris Metcalf
2017-01-14 12:51         ` [tip:timers/core] math64, timers: Fix 32bit mul_u64_u32_shr() and friends tip-bot for Peter Zijlstra
2016-12-09 10:18       ` [patch 5/6] [RFD] timekeeping: Provide optional 128bit math Peter Zijlstra
2016-12-09 17:20         ` Chris Metcalf [this message]
2016-12-08 20:49 ` [patch 6/6] [RFD] timekeeping: Get rid of cycle_t Thomas Gleixner
2016-12-08 23:43   ` David Gibson
2016-12-09  4:52 ` [patch 0/6] timekeeping: Cure the signed/unsigned wreckage John Stultz
2016-12-09  5:30 ` Peter Zijlstra

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