From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <frederic@kernel.org>
Cc: 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, 01 Dec 2020 16:53:02 +0100 [thread overview]
Message-ID: <87sg8pfrq9.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20201201150114.GZ2414@hirez.programming.kicks-ass.net>
On Tue, Dec 01 2020 at 16:01, Peter Zijlstra wrote:
> 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.
Fair enough.
next prev parent reply other threads:[~2020-12-01 15:54 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
2020-12-01 15:53 ` Thomas Gleixner [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87sg8pfrq9.fsf@nanos.tec.linutronix.de \
--to=tglx@linutronix.de \
--cc=benh@kernel.crashing.org \
--cc=borntraeger@de.ibm.com \
--cc=fenghua.yu@intel.com \
--cc=frederic@kernel.org \
--cc=gor@linux.ibm.com \
--cc=hca@linux.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mpe@ellerman.id.au \
--cc=paulus@samba.org \
--cc=peterz@infradead.org \
--cc=tony.luck@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).