From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
Tony Luck <tony.luck@intel.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Fenghua Yu <fenghua.yu@intel.com>,
Heiko Carstens <hca@linux.ibm.com>
Subject: Re: [PATCH 4/5] irqtime: Move irqtime entry accounting after irq offset incrementation
Date: Tue, 1 Dec 2020 16:01:14 +0100 [thread overview]
Message-ID: <20201201150114.GZ2414@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20201201143545.GC72897@lothringen>
On Tue, Dec 01, 2020 at 03:35:45PM +0100, Frederic Weisbecker wrote:
> And that one too makes things simple. But note that
>
> account_hardirq_enter_time()
>
> will still need some preempt count checks to see if
> this is a nested hardirq, a hardirq interrupting a softirq
> or a hardirq interrupting a task.
So the current tests get that all correct in a single function.
Splitting it out will just result in more lines to get wrong.
That is, I don't think you can do it saner than:
account_softirq_enter() := irqtime_account_irq(curr, SOFTIRQ_OFFSET);
account_softirq_exit() := irqtime_account_irq(curr, 0);
account_hardirq_enter() := irqtime_account_irq(curr, HARDIRQ_OFFSET);
account_hardirq_exit() := irqtime_account_irq(curr, 0);
Fundamentally you have to determine the previous context to determine
where to account the delta to. Note that when the previous context is
task context we throw away the delta.
next prev parent reply other threads:[~2020-12-01 15:02 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 0:12 [PATCH 0/5] irq: Reorder time handling against HARDIRQ_OFFSET on IRQ entry v2 Frederic Weisbecker
2020-12-01 0:12 ` [PATCH 1/5] sched/cputime: Remove symbol exports from IRQ time accounting Frederic Weisbecker
2020-12-01 0:12 ` [PATCH 2/5] sched/vtime: Consolidate " Frederic Weisbecker
2020-12-01 0:12 ` [PATCH 3/5] s390/vtime: Convert to consolidated " Frederic Weisbecker
2020-12-01 0:12 ` [PATCH 4/5] irqtime: Move irqtime entry accounting after irq offset incrementation Frederic Weisbecker
2020-12-01 9:20 ` Peter Zijlstra
2020-12-01 11:23 ` Frederic Weisbecker
2020-12-01 11:33 ` Thomas Gleixner
2020-12-01 11:40 ` Frederic Weisbecker
2020-12-01 13:34 ` Thomas Gleixner
2020-12-01 14:35 ` Frederic Weisbecker
2020-12-01 15:01 ` Peter Zijlstra [this message]
2020-12-01 15:53 ` Thomas Gleixner
2020-12-01 0:12 ` [PATCH 5/5] irq: Call tick_irq_enter() inside HARDIRQ_OFFSET Frederic Weisbecker
2020-12-02 11:57 [PATCH 0/5] irq: Reorder time handling against HARDIRQ_OFFSET on IRQ entry v3 Frederic Weisbecker
2020-12-02 11:57 ` [PATCH 4/5] irqtime: Move irqtime entry accounting after irq offset incrementation Frederic Weisbecker
2020-12-02 12:36 ` Peter Zijlstra
2020-12-28 2:15 ` Qais Yousef
2020-12-29 13:41 ` Frederic Weisbecker
2020-12-29 14:12 ` Qais Yousef
2020-12-29 14:30 ` Frederic Weisbecker
2020-12-29 15:58 ` Qais Yousef
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