mlx5 interrupts

[Slawa Olhovchenkov]

On Mon, Jul 20, 2020 at 01:43:39PM +0300, Konstantin Belousov wrote:

> On Sun, Jul 19, 2020 at 07:12:07PM +0300, Slawa Olhovchenkov wrote:
> > Can anybody explain what purpose of unnamed interrupts of Mellanox
> > ConnectX-5 cards?
> > 
> > I am see 19 interrupts per card. I am mean last 16 is RX queue.
> It is more correct to describe them as completion queue interrupts, they
> serve both rx and tx workqueues.
> 
> > What about first 3?
> One is for firmware memory requests notifications for UMA.
> Two others are firmware command completion and async events (like PHY
> module events or hw state notifications).
> 
> > Also I am see very high rate for irq287/irq306 -- is this good?
> You did not demostrated what you mean by 'very high rate'.
> 20 req/sec does not count as 'high', and this is the highest I see
> in your message.

Currently this is idle server and totaly interrupts count for firmware
command completion is 50x more compared to completion queue
interrupts. I am afraid to flooded at prodation load.

Also, completion queue interrupts may be pined to dedicaded CPU, what
about command completion?

> > 
> > # vmstat -i | grep -e ^int -e mlx
> > interrupt                          total       rate
> > irq286: mlx5_core0                     1          0
> > irq287: mlx5_core0               5135992         20
> > irq288: mlx5_core0                     1          0
> > irq289: mlx5_core0                 76408          0
> > irq290: mlx5_core0                 43054          0
> > irq291: mlx5_core0                 93826          0
> > irq292: mlx5_core0                 39457          0
> > irq293: mlx5_core0                 36141          0
> > irq294: mlx5_core0                 65526          0
> > irq295: mlx5_core0                 53399          0
> > irq296: mlx5_core0                120885          0
> > irq297: mlx5_core0                140690          1
> > irq298: mlx5_core0                193578          1
> > irq299: mlx5_core0                178332          1
> > irq300: mlx5_core0                 75334          0
> > irq301: mlx5_core0                207118          1
> > irq302: mlx5_core0                108803          0
> > irq303: mlx5_core0                 24356          0
> > irq304: mlx5_core0                 26713          0
> > irq305: mlx5_core1                     1          0
> > irq306: mlx5_core1               5136296         20
> > irq307: mlx5_core1                     1          0
> > irq308: mlx5_core1               3634544         14
> > irq309: mlx5_core1                 22860          0
> > irq310: mlx5_core1                564441          2
> > irq311: mlx5_core1                 30503          0
> > irq312: mlx5_core1                115549          0
> > irq313: mlx5_core1                 49815          0
> > irq314: mlx5_core1                 10272          0
> > irq315: mlx5_core1                 85875          0
> > irq316: mlx5_core1                134251          1
> > irq317: mlx5_core1                 25151          0
> > irq318: mlx5_core1                 73376          0
> > irq319: mlx5_core1                  5879          0
> > irq320: mlx5_core1                 39515          0
> > irq321: mlx5_core1                  5390          0
> > irq322: mlx5_core1                 22726          0
> > irq323: mlx5_core1                 60408          0