Re: [patch V2 0/2] genirq, proc: Speedup /proc/stat interrupt statistics

Davidlohr Bueso
2019-02-08T17:01:53Z

On Fri, 08 Feb 2019, Thomas Gleixner wrote:

>Waiman reported that on large systems with a large amount of interrupts the
>readout of /proc/stat takes a long time to sum up the interrupt
>statistics. In principle this is not a problem. but for unknown reasons
>some enterprise quality software reads /proc/stat with a high frequency.

:)

>
>The reason for this is that interrupt statistics are accounted per cpu. So
>the /proc/stat logic has to sum up the interrupt stats for each interrupt.
>
>The following series addresses this by making the interrupt statitics code
>in the core generate the sum directly and by making the loop in the
>/proc/stat read function smarter.
>
>V1 -> V2: Address review feedback: undo struct layout changes, make
> variables unsigned and add test results to the changelog.
>
>Thanks,
>
> tglx
>
>8<----------------
> fs/proc/stat.c | 29 ++++++++++++++++++++++++++---
> include/linux/irqdesc.h | 1 +
> kernel/irq/chip.c | 12 ++++++++++--
> kernel/irq/internals.h | 8 +++++++-
> kernel/irq/irqdesc.c | 7 ++++++-
> 5 files changed, 50 insertions(+), 7 deletions(-)

Reviewed-by: Davidlohr Bueso <dbueso@suse.de>