Re: [patch v2 04/14] x86/irq: Make irqstats array based

[Radu Rendec]

On Wed, 2026-03-25 at 23:52 +0100, Thomas Gleixner wrote:
> On Wed, Mar 25 2026 at 15:20, Radu Rendec wrote:
> > On Tue, 2026-03-24 at 16:32 -0400, Radu Rendec wrote:
> > 
> > I tested it, and it's very close but requires a few extra changes,
> > which I included as a patch at the bottom.
> 
> All of this is overly complicated. That can directly use the
> irq_stat_info array and therefore stays always in sync without ever
> touching that python nightmare again.

Of course! That's why you created irq_stat_info in the first place, and
the gdb/python approach is now similar to what you did on the kernel
side. I guess the solution was too obvious for either of us to see on
the first iteration :)

> Replacement patch below (works only after 5/14 obviously).

I tested it, and I can confirm it works.

> > There's one more gotcha: in the next patch (patch 5) you rename nr_irqs
> > to total_nr_irqs, and the change must be applied to interrupts.py as
> > well. It's used at the beginning of the LxInterruptList.invoke()
> > function.
> 
> Sigh, yes. This GDB python insanity is a pain, debugging it even more so.

I agree, debugging it is not very friendly. But in case you ever have
to deal with it again, you may find this helpful:
 * print() in python code works (you'll see the output in gdb);
 * there's a "set python print-stack full" command; once enabled,
   you'll see something like this:

(gdb) lx-interruptlist 
Traceback (most recent call last):
  File "/..../scripts/gdb/linux/interrupts.py", line 187, in invoke
    nr_irqs = gdb.parse_and_eval("total_nr_irqs1")
gdb.error: No symbol "total_nr_irqs1" in current context.

> ---
> diff --git a/scripts/gdb/linux/interrupts.py b/scripts/gdb/linux/interrupts.py
> index f4f715a8f0e3..7fde52317e84 100644
> --- a/scripts/gdb/linux/interrupts.py
> +++ b/scripts/gdb/linux/interrupts.py
> @@ -97,13 +97,13 @@ def show_irq_err_count(prec):
>          text += "%*s: %10u\n" % (prec, "ERR", cnt['counter'])
>      return text
>  
> -def x86_show_irqstat(prec, pfx, field, desc):
> -    irq_stat = gdb.parse_and_eval("&irq_stat")
> +def x86_show_irqstat(prec, pfx, idx, desc):
> +    irq_stat = gdb.parse_and_eval("&irq_stat.counts[%d]" %idx)
>      text = "%*s: " % (prec, pfx)
>      for cpu in cpus.each_online_cpu():
>          stat = cpus.per_cpu(irq_stat, cpu)
> -        text += "%10u " % (stat[field])
> -    text += "  %s\n" % (desc)
> +        text += "%10u " % (stat.dereference())
> +    text += desc
>      return text
>  
>  def x86_show_mce(prec, var, pfx, desc):
> @@ -115,34 +115,14 @@ def x86_show_mce(prec, var, pfx, desc):
>      return text
>  
>  def x86_show_interupts(prec):
> -    text = x86_show_irqstat(prec, "NMI", '__nmi_count', 'Non-maskable interrupts')
> -
> -    if constants.LX_CONFIG_X86_LOCAL_APIC:
> -        text += x86_show_irqstat(prec, "LOC", 'apic_timer_irqs', "Local timer interrupts")
> -        text += x86_show_irqstat(prec, "SPU", 'irq_spurious_count', "Spurious interrupts")
> -        text += x86_show_irqstat(prec, "PMI", 'apic_perf_irqs', "Performance monitoring interrupts")
> -        text += x86_show_irqstat(prec, "IWI", 'apic_irq_work_irqs', "IRQ work interrupts")
> -        text += x86_show_irqstat(prec, "RTR", 'icr_read_retry_count', "APIC ICR read retries")
> -        if utils.gdb_eval_or_none("x86_platform_ipi_callback") is not None:
> -            text += x86_show_irqstat(prec, "PLT", 'x86_platform_ipis', "Platform interrupts")
> -
> -    if constants.LX_CONFIG_SMP:
> -        text += x86_show_irqstat(prec, "RES", 'irq_resched_count', "Rescheduling interrupts")
> -        text += x86_show_irqstat(prec, "CAL", 'irq_call_count', "Function call interrupts")
> -        text += x86_show_irqstat(prec, "TLB", 'irq_tlb_count', "TLB shootdowns")
> -
> -    if constants.LX_CONFIG_X86_THERMAL_VECTOR:
> -        text += x86_show_irqstat(prec, "TRM", 'irq_thermal_count', "Thermal events interrupts")
> +    info_type = gdb.lookup_type('struct irq_stat_info')
> +    info = gdb.parse_and_eval('irq_stat_info')
>  
> -    if constants.LX_CONFIG_X86_MCE_THRESHOLD:
> -        text += x86_show_irqstat(prec, "THR", 'irq_threshold_count', "Threshold APIC interrupts")
> -
> -    if constants.LX_CONFIG_X86_MCE_AMD:
> -        text += x86_show_irqstat(prec, "DFR", 'irq_deferred_error_count', "Deferred Error APIC interrupts")
> -
> -    if constants.LX_CONFIG_X86_MCE:
> -        text += x86_show_mce(prec, "&mce_exception_count", "MCE", "Machine check exceptions")
> -        text += x86_show_mce(prec, "&mce_poll_count", "MCP", "Machine check polls")
> +    text = ""
> +    for idx in range(int(info.type.sizeof / info_type.sizeof)):
> +        pfx = info[idx]['symbol'].string()
> +        desc = info[idx]['text'].string()
> +        text += x86_show_irqstat(prec, pfx, idx, desc)
>  
>      text += show_irq_err_count(prec)
>  
> @@ -151,11 +131,6 @@ def x86_show_interupts(prec):
>          if cnt is not None:
>              text += "%*s: %10u\n" % (prec, "MIS", cnt['counter'])
>  
> -    if constants.LX_CONFIG_KVM:
> -        text += x86_show_irqstat(prec, "PIN", 'kvm_posted_intr_ipis', 'Posted-interrupt notification event')
> -        text += x86_show_irqstat(prec, "NPI", 'kvm_posted_intr_nested_ipis', 'Nested posted-interrupt event')
> -        text += x86_show_irqstat(prec, "PIW", 'kvm_posted_intr_wakeup_ipis', 'Posted-interrupt wakeup event')
> -
>      return text
>  
>  def arm_common_show_interrupts(prec):
> @@ -209,7 +184,7 @@ class LxInterruptList(gdb.Command):
>          super(LxInterruptList, self).__init__("lx-interruptlist", gdb.COMMAND_DATA)
>  
>      def invoke(self, arg, from_tty):
> -        nr_irqs = gdb.parse_and_eval("nr_irqs")
> +        nr_irqs = gdb.parse_and_eval("total_nr_irqs")
>          prec = 3
>          j = 1000
>          while prec < 10 and j <= nr_irqs: