From: Ingo Molnar <mingo@elte.hu>
To: "Metzger, Markus T" <markus.t.metzger@intel.com>
Cc: "tglx@linutronix.de" <tglx@linutronix.de>,
"hpa@zytor.com" <hpa@zytor.com>,
"markus.t.metzger@gmail.com" <markus.t.metzger@gmail.com>,
"roland@redhat.com" <roland@redhat.com>,
"eranian@googlemail.com" <eranian@googlemail.com>,
"oleg@redhat.com" <oleg@redhat.com>,
"Villacis, Juan" <juan.villacis@intel.com>,
"ak@linux.jf.intel.com" <ak@linux.jf.intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [patch 01/18] x86, bts: fix race when bts tracer is removed
Date: Fri, 3 Apr 2009 13:30:58 +0200 [thread overview]
Message-ID: <20090403113058.GE31399@elte.hu> (raw)
In-Reply-To: <928CFBE8E7CB0040959E56B4EA41A77E9271809B@irsmsx504.ger.corp.intel.com>
* Metzger, Markus T <markus.t.metzger@intel.com> wrote:
> >-----Original Message-----
> >From: Metzger, Markus T
> >Sent: Friday, April 03, 2009 8:20 AM
> >To: Ingo Molnar
>
>
> >>Also, raw use of jiffies_64 is buggy and racy. Why does this use
> >>jiffies to begin with - why not some finer grained time?
> >
> >What would be a good time to use?
>
> I found cpu_clock() declared in sched.h, which is based on TSC and
> seems to be used by the scheduler, as well. Would this be a good
> time to use?
i'd suggest trace_clock() [which maps to cpu_clock() internally], or
trace_clock_global().
See kernel/trace/trace_clock.c about the properties/tradeoffs. Since
this is a user-facing ABI, trace_clock_global() looks more
compelling, despite its global lock.
Ingo
next prev parent reply other threads:[~2009-04-03 11:31 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-02 14:54 [patch 00/18] x86, bts, ptrace, hw-branch-tracer: fixes and cleanups markus.t.metzger
2009-04-02 14:54 ` [patch 01/18] x86, bts: fix race when bts tracer is removed markus.t.metzger
2009-04-02 18:45 ` Ingo Molnar
2009-04-03 6:19 ` Metzger, Markus T
2009-04-03 7:17 ` Metzger, Markus T
2009-04-03 11:30 ` Ingo Molnar [this message]
2009-04-03 11:29 ` Ingo Molnar
2009-04-02 14:54 ` [patch 02/18] sched: add task_is_running() fucntion to sched.h markus.t.metzger
2009-04-02 14:54 ` [patch 03/18] x86, ptrace, bts: defer branch trace stopping markus.t.metzger
2009-04-02 18:40 ` Ingo Molnar
2009-04-02 14:54 ` [patch 04/18] x86, bts: wait until traced task has been scheduled out markus.t.metzger
2009-04-02 19:17 ` Ingo Molnar
2009-04-03 6:22 ` Metzger, Markus T
2009-04-03 11:32 ` Ingo Molnar
2009-04-03 11:36 ` Metzger, Markus T
2009-04-02 14:55 ` [patch 05/18] x86, bts: fix race between per-task and per-cpu branch tracing markus.t.metzger
2009-04-02 14:55 ` [patch 06/18] x86, debugctlmsr: add _on_cpu variants to debugctlmsr functions markus.t.metzger
2009-04-02 14:55 ` [patch 07/18] x86, bts, hw-branch-tracer: add _noirq variants to the debug store interface markus.t.metzger
2009-04-02 14:55 ` [patch 08/18] x86, hw-branch-tracer: allocate selftest iterator on heap markus.t.metzger
2009-04-02 14:55 ` [patch 09/18] x86, ds: fix compiler warning markus.t.metzger
2009-04-02 14:55 ` [patch 10/18] x86, ds: fix bounds check in ds selftest markus.t.metzger
2009-04-02 14:55 ` [patch 11/18] x86, ds: selftest each cpu markus.t.metzger
2009-04-02 14:55 ` [patch 12/18] x86, ds: add task tracing selftest markus.t.metzger
2009-04-02 14:55 ` [patch 13/18] x86, ds: add leakage warning markus.t.metzger
2009-04-02 19:27 ` Ingo Molnar
2009-04-03 6:42 ` Metzger, Markus T
2009-04-02 14:55 ` [patch 14/18] x86, ds: use single debug store cpu configuration markus.t.metzger
2009-04-02 19:29 ` Ingo Molnar
2009-04-03 6:46 ` Metzger, Markus T
2009-04-02 14:55 ` [patch 15/18] x86, ptrace: remove duplicate functionality markus.t.metzger
2009-04-02 14:55 ` [patch 16/18] x86, ds: dont use TIF_DEBUGCTLMSR markus.t.metzger
2009-04-02 14:55 ` [patch 17/18] x86, ds: fix bad ds_reset_pebs() markus.t.metzger
2009-04-02 14:55 ` [patch 18/18] x86, ds: support Core i7 markus.t.metzger
2009-04-02 19:22 ` [patch 00/18] x86, bts, ptrace, hw-branch-tracer: fixes and cleanups Ingo Molnar
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