From: Thomas Gleixner <tglx@linutronix.de>
To: Lukas Wunner <lukas@wunner.de>, Bjorn Helgaas <helgaas@kernel.org>
Cc: Jiri Slaby <jirislaby@kernel.org>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: IRQ domain logging?
Date: Mon, 28 Apr 2025 15:13:43 +0200 [thread overview]
Message-ID: <87frhsqvi0.ffs@tglx> (raw)
In-Reply-To: <aAijgnvHRYu_Dlqe@wunner.de>
On Wed, Apr 23 2025 at 10:23, Lukas Wunner wrote:
> On Tue, Apr 22, 2025 at 04:07:05PM -0500, Bjorn Helgaas wrote:
>> This from an arm64 system is even more obscure to me:
>>
>> NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
>> GICv3: 256 SPIs implemented
>> Root IRQ handler: gic_handle_irq
>> GICv3: GICv3 features: 16 PPIs
>> kvm [1]: vgic interrupt IRQ18
>> xhci-hcd xhci-hcd.0.auto: irq 67, io mem 0xfe800000
>>
>> I have no clue where irq 67 goes.
>
> There's quite a bit of information available in /proc/interrupts,
> /proc/irq/ and /sys/kernel/irq/, I guess that's what most people use.
/sys/kernel/debug/irq/....
Gives the most comprehensive insight into the domain hierarchy.
# cat /sys/kernel/debug/irq/irqs/204
handler: handle_edge_irq
device: 0000:01:00.0
status: 0x00000000
istate: 0x00004000
ddepth: 0
wdepth: 0
dstate: 0x1d401200
IRQD_ACTIVATED
IRQD_IRQ_STARTED
IRQD_SINGLE_TARGET
IRQD_AFFINITY_SET
IRQD_AFFINITY_ON_ACTIVATE
IRQD_CAN_RESERVE
IRQD_HANDLE_ENFORCE_IRQCTX
node: 0
affinity: 50
effectiv: 50
pending:
domain: PCI-MSIX-0000:01:00.0-12
hwirq: 0x65
chip: PCI-MSIX-0000:01:00.0
flags: 0x1430
IRQCHIP_SKIP_SET_WAKE
IRQCHIP_ONESHOT_SAFE
IRQCHIP_MOVE_DEFERRED
address_hi: 0x00000000
address_lo: 0xfee32000
msg_data: 0x00000023
parent:
domain: VECTOR
hwirq: 0xcc
chip: APIC
flags: 0x0
Vector: 35
Target: 50
move_in_progress: 0
is_managed: 0
can_reserve: 1
has_reserved: 0
cleanup_pending: 0
It shows the complete domain hierarchy for each interrupt an
irq/domains/.... gives extra information about the domains.
You need to enable GENERIC_IRQ_DEBUGFS.
Exposing this in dmesg in a comprehensible and condensed form might be
possible, but needs some thought.
So far I survived pretty good with the debugfs data.
Thanks,
tglx
next prev parent reply other threads:[~2025-04-28 13:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-22 21:07 IRQ domain logging? Bjorn Helgaas
2025-04-23 8:23 ` Lukas Wunner
2025-04-28 13:13 ` Thomas Gleixner [this message]
2025-04-23 14:19 ` Ethan Zhao
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