From: Ingo Molnar <mingo@elte.hu>
To: David Miller <davem@davemloft.net>
Cc: jamie.iles@picochip.com, linux-kernel@vger.kernel.org,
linux@arm.linux.org.uk, peterz@infradead.org
Subject: Re: [PATCH 1/2] perf tools: allow building for ARM
Date: Fri, 11 Dec 2009 11:41:26 +0100 [thread overview]
Message-ID: <20091211104126.GA22079@elte.hu> (raw)
In-Reply-To: <20091211.023808.233094506.davem@davemloft.net>
* David Miller <davem@davemloft.net> wrote:
> From: Ingo Molnar <mingo@elte.hu>
> Date: Fri, 11 Dec 2009 11:23:16 +0100
>
> >
> > * Jamie Iles <jamie.iles@picochip.com> wrote:
> >
> >> +#ifdef __arm__
> >> +#include "../../arch/arm/include/asm/unistd.h"
> >> +#define rmb() asm volatile("":::"memory")
> >> +#define cpu_relax() asm volatile("":::"memory")
> >> +#endif
> >
> > cpu_relax() looks fine, but rmb() seems not to match the one that can be
> > found in arch/arm/:
>
> I think he did it this way so it can compile in the meantime, and that
> doing it right requires runtime cpu detection to select which barrier
> instruction is even available on the current ARM cpu.
Yeah. We can merge a quick patch for it if runtime detection is
difficult - but if then such a patch should err on the side of using the
barrier instruction unconditionally - even if this causes perf to
segfault on certain (older? UP configured?) ARM cores.
Ingo
next prev parent reply other threads:[~2009-12-11 10:41 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-11 9:20 [PATCH 1/2] perf tools: allow building for ARM Jamie Iles
2009-12-11 9:21 ` [PATCH 2/2] perf tools: allow cross compiling Jamie Iles
2009-12-11 10:27 ` [tip:perf/urgent] perf tools: Allow " tip-bot for Jamie Iles
2009-12-11 12:20 ` [PATCH] perf tools: allow building for ARM (patch v2) Jamie Iles
2009-12-11 12:54 ` [tip:perf/urgent] perf tools: Allow building for ARM tip-bot for Jamie Iles
2009-12-11 13:04 ` Jamie Iles
2009-12-11 13:26 ` Ingo Molnar
2009-12-11 10:23 ` [PATCH 1/2] perf tools: allow " Ingo Molnar
2009-12-11 10:30 ` Jamie Iles
2009-12-11 10:38 ` Ingo Molnar
2009-12-11 11:01 ` Jamie Iles
2009-12-11 11:26 ` Mikael Pettersson
2009-12-11 21:22 ` Russell King - ARM Linux
[not found] ` <000101ca7a50$b3e2ad70$1ba80850$@deacon@arm.com>
2009-12-11 11:02 ` Ingo Molnar
2009-12-11 11:08 ` Pekka Enberg
2009-12-11 10:38 ` David Miller
2009-12-11 10:41 ` Ingo Molnar [this message]
2009-12-11 11:48 ` Jamie Iles
2009-12-11 12:48 ` Ingo Molnar
2009-12-11 21:19 ` Russell King - ARM Linux
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