ctl_events operation & speed

Hi,

I'm using a small/simple/quick IRQ handler that loads data into a short circular buffer, then does

        ctl_interrupt_count++;
        ctl_events_set_clear( &irq_events, IRQ_EVT_USART3_RX, 0 );
        ctl_interrupt_count--;

to send an event to get a highest-priority task to unload the data.

I'd expected that task to be run very quickly, but it appears to be waiting on a timer tick, so my IRQ backend task runs much later than I expected.

Is there something else I need to do to get the task to run mucho presto, please?

Thanks.