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authorJoe Korty <joe.korty@ccur.com>2007-10-17 12:04:40 -0400
committerThomas Gleixner <tglx@inhelltoy.tec.linutronix.de>2007-10-17 14:16:53 -0400
commit38e760a1335ffaca5a08624a9aed6fe2055c2c98 (patch)
treec313888b750a56db7c9c09c8af5be830bb75b81e /Documentation
parent9aa8d7195acb18fc436847f6c66a97f8359ad54d (diff)
x86: expand /proc/interrupts to include missing vectors, v2
Add missing IRQs and IRQ descriptions to /proc/interrupts. /proc/interrupts is most useful when it displays every IRQ vector in use by the system, not just those somebody thought would be interesting. This patch inserts the following vector displays to the i386 and x86_64 platforms, as appropriate: rescheduling interrupts TLB flush interrupts function call interrupts thermal event interrupts threshold interrupts spurious interrupts A threshold interrupt occurs when ECC memory correction is occuring at too high a frequency. Thresholds are used by the ECC hardware as occasional ECC failures are part of normal operation, but long sequences of ECC failures usually indicate a memory chip that is about to fail. Thermal event interrupts occur when a temperature threshold has been exceeded for some CPU chip. IIRC, a thermal interrupt is also generated when the temperature drops back to a normal level. A spurious interrupt is an interrupt that was raised then lowered by the device before it could be fully processed by the APIC. Hence the apic sees the interrupt but does not know what device it came from. For this case the APIC hardware will assume a vector of 0xff. Rescheduling, call, and TLB flush interrupts are sent from one CPU to another per the needs of the OS. Typically, their statistics would be used to discover if an interrupt flood of the given type has been occuring. AK: merged v2 and v4 which had some more tweaks AK: replace Local interrupts with Local timer interrupts AK: Fixed description of interrupt types. [ tglx: arch/x86 adaptation ] [ mingo: small cleanup ] Signed-off-by: Joe Korty <joe.korty@ccur.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Tim Hockin <thockin@hockin.org> Cc: Andi Kleen <ak@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/proc.txt30
1 files changed, 29 insertions, 1 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 4a37e25e694c..e5c1df52a876 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -347,7 +347,35 @@ connects the CPUs in a SMP system. This means that an error has been detected,
347the IO-APIC automatically retry the transmission, so it should not be a big 347the IO-APIC automatically retry the transmission, so it should not be a big
348problem, but you should read the SMP-FAQ. 348problem, but you should read the SMP-FAQ.
349 349
350In this context it could be interesting to note the new irq directory in 2.4. 350In 2.6.2* /proc/interrupts was expanded again. This time the goal was for
351/proc/interrupts to display every IRQ vector in use by the system, not
352just those considered 'most important'. The new vectors are:
353
354 THR -- interrupt raised when a machine check threshold counter
355 (typically counting ECC corrected errors of memory or cache) exceeds
356 a configurable threshold. Only available on some systems.
357
358 TRM -- a thermal event interrupt occurs when a temperature threshold
359 has been exceeded for the CPU. This interrupt may also be generated
360 when the temperature drops back to normal.
361
362 SPU -- a spurious interrupt is some interrupt that was raised then lowered
363 by some IO device before it could be fully processed by the APIC. Hence
364 the APIC sees the interrupt but does not know what device it came from.
365 For this case the APIC will generate the interrupt with a IRQ vector
366 of 0xff. This might also be generated by chipset bugs.
367
368 RES, CAL, TLB -- rescheduling, call and TLB flush interrupts are
369 sent from one CPU to another per the needs of the OS. Typically,
370 their statistics are used by kernel developers and interested users to
371 determine the occurance of interrupt of the given type.
372
373The above IRQ vectors are displayed only when relevent. For example,
374the threshold vector does not exist on x86_64 platforms. Others are
375suppressed when the system is a uniprocessor. As of this writing, only
376i386 and x86_64 platforms support the new IRQ vector displays.
377
378Of some interest is the introduction of the /proc/irq directory to 2.4.
351It could be used to set IRQ to CPU affinity, this means that you can "hook" an 379It could be used to set IRQ to CPU affinity, this means that you can "hook" an
352IRQ to only one CPU, or to exclude a CPU of handling IRQs. The contents of the 380IRQ to only one CPU, or to exclude a CPU of handling IRQs. The contents of the
353irq subdir is one subdir for each IRQ, and one file; prof_cpu_mask 381irq subdir is one subdir for each IRQ, and one file; prof_cpu_mask