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From: Richard Henderson <rth@twiddle.net>
To: Paul Mackerras <paulus@samba.org>, t@twiddle.net
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	linuxppc-dev@ozlabs.org
Subject: Re: [RFC/PATCH] Make powerpc64 use __thread for per-cpu variables
Date: Wed, 10 May 2006 08:47:02 -0700	[thread overview]
Message-ID: <20060510154702.GA28938@twiddle.net> (raw)
In-Reply-To: <17505.26159.807484.477212@cargo.ozlabs.ibm.com>

On Wed, May 10, 2006 at 02:03:59PM +1000, Paul Mackerras wrote:
> With this patch, 64-bit powerpc uses __thread for per-cpu variables.

How do you plan to address the compiler optimizing

	__thread int foo;
	{
	  use(foo);
	  schedule();
	  use(foo);
	}

into

	{
	  int *tmp = &foo;	// tls arithmetic here
	  use(*tmp);
	  schedule();
	  use(*tmp);
	}

Across the schedule, we may have changed cpus, making the cached
address invalid.


r~

WARNING: multiple messages have this Message-ID (diff)
From: Richard Henderson <rth@twiddle.net>
To: Paul Mackerras <paulus@samba.org>
Cc: linux-arch@vger.kernel.org, linuxppc-dev@ozlabs.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC/PATCH] Make powerpc64 use __thread for per-cpu variables
Date: Wed, 10 May 2006 08:47:13 -0700	[thread overview]
Message-ID: <20060510154702.GA28938@twiddle.net> (raw)
In-Reply-To: <17505.26159.807484.477212@cargo.ozlabs.ibm.com>

On Wed, May 10, 2006 at 02:03:59PM +1000, Paul Mackerras wrote:
> With this patch, 64-bit powerpc uses __thread for per-cpu variables.

How do you plan to address the compiler optimizing

	__thread int foo;
	{
	  use(foo);
	  schedule();
	  use(foo);
	}

into

	{
	  int *tmp = &foo;	// tls arithmetic here
	  use(*tmp);
	  schedule();
	  use(*tmp);
	}

Across the schedule, we may have changed cpus, making the cached
address invalid.


r~

WARNING: multiple messages have this Message-ID (diff)
From: Richard Henderson <rth@twiddle.net>
To: Paul Mackerras <paulus@samba.org>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	linuxppc-dev@ozlabs.org
Subject: Re: [RFC/PATCH] Make powerpc64 use __thread for per-cpu variables
Date: Wed, 10 May 2006 08:47:13 -0700	[thread overview]
Message-ID: <20060510154702.GA28938@twiddle.net> (raw)
In-Reply-To: <17505.26159.807484.477212@cargo.ozlabs.ibm.com>

On Wed, May 10, 2006 at 02:03:59PM +1000, Paul Mackerras wrote:
> With this patch, 64-bit powerpc uses __thread for per-cpu variables.

How do you plan to address the compiler optimizing

	__thread int foo;
	{
	  use(foo);
	  schedule();
	  use(foo);
	}

into

	{
	  int *tmp = &foo;	// tls arithmetic here
	  use(*tmp);
	  schedule();
	  use(*tmp);
	}

Across the schedule, we may have changed cpus, making the cached
address invalid.


r~

  parent reply	other threads:[~2006-05-10 15:47 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-10  4:03 [RFC/PATCH] Make powerpc64 use __thread for per-cpu variables Paul Mackerras
2006-05-10  5:16 ` Olof Johansson
2006-05-10  5:16   ` Olof Johansson
2006-05-10  5:35   ` Alan Modra
2006-05-10  5:35     ` Alan Modra
2006-05-10  6:22   ` David S. Miller
2006-05-10  6:22     ` David S. Miller
2006-05-10  6:29   ` Paul Mackerras
2006-05-10  6:29     ` Paul Mackerras
2006-05-10  6:39     ` David S. Miller
2006-05-10  6:39       ` David S. Miller
2006-05-10  7:21       ` Benjamin Herrenschmidt
2006-05-10  7:21         ` Benjamin Herrenschmidt
2006-05-10 10:14         ` David Howells
2006-05-10 10:14           ` David Howells
2006-05-10  7:41       ` Paul Mackerras
2006-05-10  7:41         ` Paul Mackerras
2006-05-10 15:47 ` Richard Henderson [this message]
2006-05-10 15:47   ` Richard Henderson
2006-05-10 15:47   ` Richard Henderson
2006-05-10 18:04   ` Steven Rostedt
2006-05-10 18:04     ` Steven Rostedt
2006-05-10 19:40   ` David S. Miller
2006-05-10 19:40     ` David S. Miller
2006-05-10 21:05     ` Paul Mackerras
2006-05-10 21:05       ` Paul Mackerras
2006-05-10 22:25       ` David S. Miller
2006-05-10 22:25         ` David S. Miller
2006-05-10 23:17       ` Segher Boessenkool
2006-05-10 23:17         ` Segher Boessenkool
2006-05-11  0:22         ` Richard Henderson
2006-05-11  0:22           ` Richard Henderson
2006-05-11 23:41           ` Segher Boessenkool
2006-05-11 23:41             ` Segher Boessenkool
2006-05-11  1:04       ` Alan Modra
2006-05-11  1:04         ` Alan Modra
2006-05-11  1:21         ` Paul Mackerras
2006-05-11  1:21           ` Paul Mackerras
2006-05-11  2:01           ` Alan Modra
2006-05-11  2:01             ` Alan Modra
2006-05-11 23:42           ` Segher Boessenkool
2006-05-11 23:42             ` Segher Boessenkool
2006-05-10 23:05   ` Paul Mackerras
2006-05-10 23:05     ` Paul Mackerras
2006-05-10 23:44     ` Paul Mackerras
2006-05-11  0:11       ` David S. Miller
2006-05-11  0:11         ` David S. Miller
2006-05-18 23:50         ` Paul Mackerras
2006-05-18 23:50           ` Paul Mackerras

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