From: Richard Henderson <rth@redhat.com>
To: Roland McGrath <roland@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>,
linux-kernel@vger.kernel.org, mingo@elte.hu,
mathieu.desnoyers@polymtl.ca, tglx@linutronix.de,
rostedt@goodmis.org, ak@suse.de, mhiramat@redhat.com
Subject: Re: [PATCH 0/4] jump label patches
Date: Wed, 07 Oct 2009 08:35:09 -0700 [thread overview]
Message-ID: <4ACCB52D.3020104@redhat.com> (raw)
In-Reply-To: <20091007001436.B5FE9A8C@magilla.sf.frob.com>
On 10/06/2009 05:14 PM, Roland McGrath wrote:
> Kernel builds usually use -Os. Is there anything else we can do now (4.4)
> to influence this placement (while keeping the unlikely target block inside
> a scope, i.e. macro, with the asm goto)?
I think -Os includes -freorder-blocks as well.
> if (0) yes: maybe = 1;
Anything with "if (0)" in it (even with __builtin_expect) is going to be
folded away too early to be useful.
I can't think of any way to manipulate block placement from the source
level at this time that doesn't add more code along the fast path,
obviating the asm goto.
r~
next prev parent reply other threads:[~2009-10-07 15:36 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-24 23:17 [PATCH 0/4] jump label patches Jason Baron
2009-09-24 23:17 ` [PATCH 1/4] jump label - make init_kernel_text() global Jason Baron
2009-10-01 11:20 ` Ingo Molnar
2009-10-01 12:58 ` Mathieu Desnoyers
2009-10-01 20:39 ` Jason Baron
2009-10-03 10:43 ` Ingo Molnar
2009-10-03 12:39 ` Mathieu Desnoyers
2009-10-07 1:54 ` Steven Rostedt
2009-10-07 2:32 ` Mathieu Desnoyers
2009-10-07 3:10 ` Masami Hiramatsu
2009-10-07 3:23 ` Mathieu Desnoyers
2009-10-07 3:29 ` Mathieu Desnoyers
2009-10-07 12:56 ` Steven Rostedt
2009-10-07 13:35 ` Mathieu Desnoyers
2009-09-24 23:17 ` [PATCH 2/4] jump label - base patch Jason Baron
2009-09-25 0:49 ` Roland McGrath
2009-09-26 10:21 ` Steven Rostedt
2009-10-01 11:36 ` Ingo Molnar
2009-09-24 23:17 ` [PATCH 3/4] jump label - add module support Jason Baron
2009-09-24 23:18 ` [PATCH 4/4] jump label - tracepoint implementation Jason Baron
2009-10-06 5:39 ` [PATCH 0/4] jump label patches Roland McGrath
2009-10-06 14:07 ` Jason Baron
2009-10-06 23:24 ` Richard Henderson
2009-10-07 0:14 ` Roland McGrath
2009-10-07 15:35 ` Richard Henderson [this message]
2009-10-06 6:04 ` Roland McGrath
2009-10-06 14:09 ` Steven Rostedt
2009-10-06 14:13 ` Masami Hiramatsu
2009-10-06 14:30 ` Mathieu Desnoyers
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