From: Jonathan Austin <jonathan.austin@arm.com>
To: "André Hentschel" <nerv@dawncrow.de>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Will Deacon <Will.Deacon@arm.com>
Subject: Re: arm: Only load TLS values when needed
Date: Wed, 14 Aug 2013 17:20:40 +0100 [thread overview]
Message-ID: <520BAE58.3060600@arm.com> (raw)
In-Reply-To: <520B8F37.4040609@dawncrow.de>
Hi André,
On 14/08/13 15:07, André Hentschel wrote:
> Hi Jonathan,
> Any updates on this?
>
I was holding out to see the version with ldrd at the top, as discussed
below - I never saw a version with that change? I'd meant to ping you to
see if that was coming, sorry.
[...]
>>> [...]
>>>>> Now we've only got one instruction between the store and the load
>>>>> and risk stalling the pipeline...
>>>>>
>>>>> Dave M cautiously says "The ancient advice was that one instruction
>>>>> was enough" but this is very core dependent... I wonder if anyone
>>>>> has a good idea about whether this is an issue here...?
>>>>
>>>> We could use a ldrd at the top, that'd be nearly what we have right
>>>> now, don't we?
>>>
>>> Yea, that'd be good - as far as I can see from an 1136 TRM, the ldrd *may* be two cycles (depending on alignment of the words) but the ldr and ldrne will always be two cycles. Ahhh, the joys of modifying the fast path ;)
Was expecting to see something that reflected this discussion,
Jonny
next prev parent reply other threads:[~2013-08-14 16:20 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-15 17:14 arm: Only load TLS values when needed André Hentschel
2013-07-15 17:14 ` André Hentschel
2013-07-16 17:31 ` Jonathan Austin
2013-07-16 17:31 ` Jonathan Austin
2013-07-16 19:27 ` André Hentschel
2013-07-16 19:27 ` André Hentschel
2013-07-17 11:10 ` Jonathan Austin
2013-07-17 11:10 ` Jonathan Austin
2013-07-17 19:49 ` André Hentschel
2013-07-17 19:49 ` André Hentschel
2013-08-14 14:07 ` André Hentschel
2013-08-14 16:20 ` Jonathan Austin [this message]
2013-08-14 21:21 ` André Hentschel
2013-08-15 17:29 ` Jonathan Austin
2013-08-15 17:29 ` Jonathan Austin
2013-08-15 18:27 ` André Hentschel
2013-08-15 18:27 ` André Hentschel
2013-08-15 18:27 ` André Hentschel
2013-08-26 19:19 ` André Hentschel
2013-08-26 19:19 ` André Hentschel
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