From: Jan Kiszka <jan.kiszka@siemens.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Christoph Hellwig <hch@infradead.org>,
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
Gregory Haskins <ghaskins@novell.com>,
Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
Thomas Gleixner <tglx@linutronix.de>,
Tim Bird <tim.bird@am.sony.com>, Sam Ravnborg <sam@ravnborg.org>,
"Frank Ch. Eigler" <fche@redhat.com>,
John Stultz <johnstul@us.ibm.com>,
Arjan van de Ven <arjan@infradead.org>,
Steven Rostedt <srostedt@redhat.com>
Subject: Re: [PATCH 02/22 -v7] Add basic support for gcc profiler instrumentation
Date: Wed, 30 Jan 2008 14:21:01 +0100 [thread overview]
Message-ID: <47A079BD.8020106@siemens.com> (raw)
In-Reply-To: <20080130031840.337019504@goodmis.org>
Steven Rostedt wrote:
> --- linux-mcount.git.orig/arch/x86/kernel/entry_32.S 2008-01-29 16:59:15.000000000 -0500
> +++ linux-mcount.git/arch/x86/kernel/entry_32.S 2008-01-29 17:26:18.000000000 -0500
> @@ -75,6 +75,31 @@ DF_MASK = 0x00000400
> NT_MASK = 0x00004000
> VM_MASK = 0x00020000
>
> +#ifdef CONFIG_MCOUNT
> +.globl mcount
> +mcount:
> + /* unlikely(mcount_enabled) */
> + cmpl $0, mcount_enabled
> + jnz trace
> + ret
(and the corresponding 64-bit version)
Is the impact of this change on the (already expensive) mcount_enabled
case negligible? I worried about use cases where we want to gain some
(relative) worst-case numbers via these instrumentations.
In my personal priority scheme, CONFIG_MCOUNT=y && !mcount_enabled comes
after mcount_enabled.
Jan
--
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux
next prev parent reply other threads:[~2008-01-30 13:26 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-30 3:15 [PATCH 00/22 -v7] mcount and latency tracing utility -v7 Steven Rostedt
2008-01-30 3:15 ` [PATCH 01/22 -v7] printk - dont wakeup klogd with interrupts disabled Steven Rostedt
2008-01-30 3:15 ` [PATCH 02/22 -v7] Add basic support for gcc profiler instrumentation Steven Rostedt
2008-01-30 8:46 ` Peter Zijlstra
2008-01-30 13:08 ` Steven Rostedt
2008-01-30 14:09 ` Steven Rostedt
2008-01-30 14:25 ` Peter Zijlstra
2008-02-01 22:34 ` Paul E. McKenney
2008-02-02 1:56 ` Steven Rostedt
2008-02-02 21:41 ` Paul E. McKenney
2008-02-04 17:09 ` Steven Rostedt
2008-02-04 21:40 ` Paul E. McKenney
2008-02-04 22:03 ` Steven Rostedt
2008-02-04 22:41 ` Mathieu Desnoyers
2008-02-05 6:11 ` Paul E. McKenney
2008-02-05 5:13 ` Paul E. McKenney
2008-01-30 13:21 ` Jan Kiszka [this message]
2008-01-30 13:53 ` Steven Rostedt
2008-01-30 14:28 ` Steven Rostedt
2008-01-30 3:15 ` [PATCH 03/22 -v7] Annotate core code that should not be traced Steven Rostedt
2008-01-30 3:15 ` [PATCH 04/22 -v7] x86_64: notrace annotations Steven Rostedt
2008-01-30 3:15 ` [PATCH 05/22 -v7] add notrace annotations to vsyscall Steven Rostedt
2008-01-30 8:49 ` Peter Zijlstra
2008-01-30 13:15 ` Steven Rostedt
2008-01-30 3:15 ` [PATCH 06/22 -v7] handle accurate time keeping over long delays Steven Rostedt
2008-01-30 3:15 ` [PATCH 07/22 -v7] initialize the clock source to jiffies clock Steven Rostedt
2008-01-30 3:15 ` [PATCH 08/22 -v7] add get_monotonic_cycles Steven Rostedt
2008-01-30 3:15 ` [PATCH 09/22 -v7] add notrace annotations to timing events Steven Rostedt
2008-01-30 3:15 ` [PATCH 10/22 -v7] mcount based trace in the form of a header file library Steven Rostedt
2008-01-30 3:15 ` [PATCH 11/22 -v7] Add context switch marker to sched.c Steven Rostedt
2008-01-30 3:15 ` [PATCH 12/22 -v7] Make the task State char-string visible to all Steven Rostedt
2008-01-30 3:15 ` [PATCH 13/22 -v7] Add tracing of context switches Steven Rostedt
2008-01-30 3:15 ` [PATCH 14/22 -v7] Generic command line storage Steven Rostedt
2008-01-30 3:15 ` [PATCH 15/22 -v7] trace generic call to schedule switch Steven Rostedt
2008-01-30 3:15 ` [PATCH 16/22 -v7] Add marker in try_to_wake_up Steven Rostedt
2008-01-30 3:15 ` [PATCH 17/22 -v7] mcount tracer for wakeup latency timings Steven Rostedt
2008-01-30 9:31 ` Peter Zijlstra
2008-01-30 13:18 ` Steven Rostedt
2008-01-30 3:15 ` [PATCH 18/22 -v7] Trace irq disabled critical timings Steven Rostedt
2008-01-30 3:15 ` [PATCH 19/22 -v7] trace preempt off " Steven Rostedt
2008-01-30 9:40 ` Peter Zijlstra
2008-01-30 13:40 ` Steven Rostedt
2008-01-30 3:15 ` [PATCH 20/22 -v7] Add markers to various events Steven Rostedt
2008-01-30 3:15 ` [PATCH 21/22 -v7] Add event tracer Steven Rostedt
2008-01-30 3:15 ` [PATCH 22/22 -v7] Critical latency timings histogram Steven Rostedt
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