Just for the record, all tests you've run are with the upper irq_poll_budget of 256 [1]?
Yes, but that's the point, I never ever reach this budget because I'm only processing 1-2 completions per interrupt.
We (Hannes and me) recently stumbed accross this when trying to poll for more than 256 queue entries in the drivers we've been testing.
What do you mean by stumbed? irq-poll should be agnostic to the fact that drivers can poll more than their given budget?
Did your system load reduce with irq polling? In theory it should but I have seen increases with AHCI at least according to fio. IIRC Hannes saw decreases with his SAS HBA tests, as expected.
I didn't see any reduction. When I tested on a single cpu core (to simplify for a single queue) the cpu was at 100% cpu but got less iops (which makes sense, a single cpu-core is not enough to max out the nvme device, at least not the core I'm using). Before irqpoll I got ~230 KIOPs on a single cpu-core and after irqpoll I got ~205 KIOPs which is consistent with the ~10% iops decrease I've reported in the original submission. -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
