Re: [PATCH v5 6/7] genirq: Adaptive Global Software Interrupt Moderation (GSIM).

[sashiko-bot@kernel.org]

> GSIM helps keeping system load (as defined later) under control, but
> the use of a fixed moderation delay causes unnecessary latency when the
> system load is already low.
> 
> We focus on two types of system load related to interrupts:
> - total device interrupt rates. Some platforms show severe I/O
>   performance degradation with more than 1-2 Mintr/s across the entire
>   system. This affects especially server-class hardware with hundreds of
>   interrupt sources (NIC or SSD queues from many physical or virtualized
>   devices).
> - percentage of time spent in hardirq. This can become problematic in
>   presence of large numbers of interrupt sources hitting individual CPUs
>   (for instance, as a result of attempts to isolate application CPUs
>   from interrupt load).
> 
> [ ... ]
> hardirq_percent (delay_us = 200, target_intr_rate=0, iodepth 128)
> hardirq%	1	10	20	30	40	50	60	70
> KIOPS		13900	13800	13300	12100	10400	8600	7400	6500
> 
> Signed-off-by: Luigi Rizzo <lrizzo@google.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260819124341.4185621-1-lrizzo@google.com?part=6