I write a device driver to receive data from the hardware. The logic is when device data is ready, it will send an irq to the Linux host. The communication interface is SPI. However, the SPI controller driver to read data in the machine can not be used in irq immediately, because it will sleep.

So, I use "request_threaded_irq" to create a thread irq and put the data read function into the bottom irq.

unfortunately, I found the bottom of the irq has a large and unstable delay, varying from tens of microseconds to hundreds of microseconds.

My question is, is there a method to to make the time delay less than a value, such as increase the bottom irq priority ?