From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
rafael@kernel.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org, nicolas.pitre@linaro.org,
vincent.guittot@linaro.org
Subject: Re: [RFC V2 1/2] irq: Add a framework to measure interrupt timings
Date: Thu, 21 Jan 2016 21:27:11 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.11.1601212114480.3886@nanos> (raw)
In-Reply-To: <20160121100834.GM6356@twins.programming.kicks-ass.net>
On Thu, 21 Jan 2016, Peter Zijlstra wrote:
> On Thu, Jan 21, 2016 at 10:50:27AM +0100, Daniel Lezcano wrote:
>
> > Actually, the handle passes dev_id in order to let the irqtimings to sort
> > out a shared interrupt and prevent double sampling. In other words, for
> > shared interrupts, statistics should be per t-uple(irq , dev_id) but that is
> > something I did not implemented ATM.
> >
> > IMO, the handler is at the right place. The prediction code does not take
> > care of the shared interrupts yet.
>
> That certainly added to the confusion. But if you want per dev_id stats,
> the whole alloc framework is 'broken' too, for it allocates the stuff
> per irq.
>
> > I tried to find a platform with shared interrupts in the ones I have
> > available around me but I did not find any. Are the shared interrupts
> > something used nowadays or coming from legacy hardware ? What is the
> > priority to handle the shared interrupts in the prediction code ?
>
> They're less common (thankfully) than they used to be, but I still have
> them:
>
> root@ivb-ep:~# cat /proc/interrupts | grep ","
> 0 IO-APIC 5-fasteoi i801_smbus, i801_smbus
Hardly something which is worth to add the extra complexity.
> root@wsm-ep:~# cat /proc/interrupts | grep ","
> 18: 0 0 IO-APIC 18-fasteoi ehci_hcd:usb1, uhci_hcd:usb6
> 23: 3 927 IO-APIC 23-fasteoi ehci_hcd:usb2, uhci_hcd:usb4
Stick the USB thingy into the XHCI port :)
> 19: 9695230 19577242 .... IO-APIC 19-fasteoi uhci_hcd:usb5, ata_piix
> root@snb:~# cat /proc/interrupts | grep ","
> 19: 11058485 IO-APIC 19-fasteoi ata_piix, ata_piix
Go to the BIOS and enable AHCI mode. Both the snb and the wsm-ep chipsets can
be switched between legacy piix and ahci mode :)
You seem to have a faible for last century hardware.
> Also there's a whole host of SOCs that has them.
And one of the reasons is, that a lot of drivers do not support msi, while
these embedded beasts support MSI on almost every peripheral, at least the
newer ones.
Thanks,
tglx
next prev parent reply other threads:[~2016-01-21 20:28 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-06 15:22 [RFC PATCH 0/2] IRQ based next prediction Daniel Lezcano
2016-01-06 15:22 ` [RFC PATCH 1/2] irq: Add a framework to measure interrupt timings Daniel Lezcano
2016-01-08 15:31 ` Thomas Gleixner
2016-01-12 11:42 ` Daniel Lezcano
2016-01-06 15:22 ` [RFC PATCH 2/2] sched: idle: IRQ based next prediction for idle period Daniel Lezcano
2016-01-06 17:40 ` Nicolas Pitre
2016-01-07 15:42 ` Daniel Lezcano
2016-01-12 19:27 ` Nicolas Pitre
2016-01-10 22:37 ` Daniel Lezcano
2016-01-10 22:46 ` Nicolas Pitre
2016-01-10 22:58 ` Daniel Lezcano
2016-01-10 23:13 ` Nicolas Pitre
2016-01-08 15:43 ` Thomas Gleixner
2016-01-12 12:41 ` Daniel Lezcano
2016-01-12 13:42 ` Thomas Gleixner
2016-01-12 14:16 ` Daniel Lezcano
2016-01-12 14:26 ` Thomas Gleixner
2016-01-12 14:52 ` Daniel Lezcano
2016-01-12 15:12 ` Thomas Gleixner
2016-01-12 16:04 ` Daniel Lezcano
2016-01-13 9:17 ` Thomas Gleixner
2016-01-18 13:21 ` Daniel Lezcano
2016-01-20 15:41 ` Thomas Gleixner
2016-01-20 16:00 ` [RFC V2 0/2] IRQ based next prediction Daniel Lezcano
2016-01-20 16:00 ` [RFC V2 1/2] irq: Add a framework to measure interrupt timings Daniel Lezcano
2016-01-20 17:55 ` Thomas Gleixner
2016-01-21 9:25 ` Daniel Lezcano
2016-01-21 10:27 ` Thomas Gleixner
2016-01-20 19:07 ` Peter Zijlstra
2016-01-20 19:57 ` Thomas Gleixner
2016-01-20 20:04 ` Nicolas Pitre
2016-01-20 20:20 ` Peter Zijlstra
2016-01-20 20:22 ` Thomas Gleixner
2016-01-21 9:50 ` Daniel Lezcano
2016-01-21 10:08 ` Peter Zijlstra
2016-01-21 12:38 ` Daniel Lezcano
2016-01-21 20:27 ` Thomas Gleixner [this message]
2016-01-21 13:52 ` Thomas Gleixner
2016-01-21 14:19 ` Daniel Lezcano
2016-01-21 18:56 ` Thomas Gleixner
2016-01-22 10:15 ` Peter Zijlstra
2016-01-21 9:26 ` Daniel Lezcano
2016-01-20 19:28 ` Peter Zijlstra
2016-01-21 9:53 ` Daniel Lezcano
2016-01-20 16:00 ` [RFC V2 2/2] sched: idle: IRQ based next prediction for idle period Daniel Lezcano
2016-01-20 17:46 ` Nicolas Pitre
2016-01-20 18:44 ` Peter Zijlstra
2016-01-21 10:03 ` Daniel Lezcano
2016-01-20 19:02 ` Peter Zijlstra
2016-01-20 19:17 ` Nicolas Pitre
2016-01-20 19:29 ` Peter Zijlstra
2016-01-20 19:34 ` Peter Zijlstra
2016-01-20 19:40 ` Peter Zijlstra
2016-01-20 19:57 ` Nicolas Pitre
2016-01-20 20:22 ` Peter Zijlstra
2016-01-20 19:49 ` Thomas Gleixner
2016-01-21 13:54 ` Daniel Lezcano
2016-01-21 14:12 ` Thomas Gleixner
2016-01-20 16:00 ` [RFC V2 0/2] IRQ based next prediction Daniel Lezcano
2016-01-20 16:00 ` [RFC V2 1/2] irq: Add a framework to measure interrupt timings Daniel Lezcano
2016-01-20 16:00 ` [RFC V2 2/2] sched: idle: IRQ based next prediction for idle period Daniel Lezcano
2016-01-20 20:14 ` Nicolas Pitre
2016-01-21 13:04 ` Daniel Lezcano
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