From: Peter Zijlstra <peterz@infradead.org>
To: Venkatesh Pallipadi <venki@google.com>
Cc: Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
linux-kernel@vger.kernel.org, Paul Turner <pjt@google.com>,
Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH 3/7] Add IRQ_TIME_ACCOUNTING, finer accounting of irq time -v3
Date: Sat, 02 Oct 2010 01:14:33 +0200 [thread overview]
Message-ID: <1285974873.2144.65.camel@laptop> (raw)
In-Reply-To: <AANLkTi=b2NaXOS05tT69hdmddxPPc5OxxnZ0qG0ZZZYe@mail.gmail.com>
On Fri, 2010-10-01 at 10:29 -0700, Venkatesh Pallipadi wrote:
> So, on x86, sched_clock_stable is not set on all other kind of CPUs
> and my test system happens to be one of them. So, sched_clock_cpu()
> falls back to tick based even when TSC is not marked unstable and
> clocksource is using TSC for timing.
It is never tick based!! It's tick augmented! Because TSC is such a
piece of crap we use external (slow) means of determining a window in
which the TSC should live and then use the TSC to generate high
resolution offsets inside that.
So even if your usage is in the hardirq context that moves that window
it should all work out.
next prev parent reply other threads:[~2010-10-01 23:14 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-29 19:21 Proper kernel irq time accounting -v3 Venkatesh Pallipadi
2010-09-29 19:21 ` [PATCH 1/7] si time accounting accounts bh_disable'd time to si -v3 Venkatesh Pallipadi
2010-09-30 11:04 ` Peter Zijlstra
2010-09-30 16:26 ` Venkatesh Pallipadi
2010-10-01 23:16 ` Peter Zijlstra
2010-10-02 15:42 ` Venkatesh Pallipadi
2010-10-03 0:34 ` Peter Zijlstra
2010-10-04 16:54 ` Venkatesh Pallipadi
2010-09-29 19:21 ` [PATCH 2/7] Consolidate account_system_vtime extern declaration -v3 Venkatesh Pallipadi
2010-09-29 19:21 ` [PATCH 3/7] Add IRQ_TIME_ACCOUNTING, finer accounting of irq time -v3 Venkatesh Pallipadi
2010-09-30 11:06 ` Peter Zijlstra
2010-09-30 16:29 ` Venkatesh Pallipadi
2010-09-30 20:38 ` Venkatesh Pallipadi
2010-10-01 11:46 ` Peter Zijlstra
2010-10-01 16:51 ` Venkatesh Pallipadi
2010-10-01 17:29 ` Venkatesh Pallipadi
2010-10-01 23:14 ` Peter Zijlstra [this message]
2010-10-01 23:32 ` Venkatesh Pallipadi
2010-10-02 10:53 ` Peter Zijlstra
2010-10-02 15:26 ` Venkatesh Pallipadi
2010-10-03 0:26 ` Peter Zijlstra
2010-10-01 11:45 ` Peter Zijlstra
2010-09-29 19:21 ` [PATCH 4/7] x86: Add IRQ_TIME_ACCOUNTING in x86 -v3 Venkatesh Pallipadi
2010-09-29 19:21 ` [PATCH 5/7] sched: Do not account irq time to current task -v3 Venkatesh Pallipadi
2010-09-29 19:21 ` [PATCH 6/7] sched: Remove irq time from available CPU power -v3 Venkatesh Pallipadi
2010-09-29 19:21 ` [PATCH 7/7] Export per cpu hardirq and softirq time in proc -v3 Venkatesh Pallipadi
2010-09-30 7:59 ` Proper kernel irq time accounting -v3 Andi Kleen
2010-09-30 16:37 ` Venkatesh Pallipadi
2010-09-30 17:36 ` Andi Kleen
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