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

[Davidlohr Bueso]

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@xxxxxxx>