Using AP adapter interrupts
To improve cryptographic performance for Linux® instances that run in LPAR mode, use AP interrupts.
About this task
Using AP interrupts instead of the polling thread frees one processor while cryptographic requests are processed.
During initialization, the zcrypt device driver checks whether AP adapter interrupts are supported by the hardware. If so, polling is disabled and the interrupt mechanism is automatically used.
To query whether AP adapter interrupts are used, read the sysfs attribute interrupt of the device. Another interrupt attribute at the AP bus level, /sys/bus/ap/ap_interrupts, indicates that the AP bus is able to handle interrupts.
Example
To read the interrupt attribute for a device 0x3e with
domain 0xf, issue:
# cat /sys/bus/ap/devices/card3e/3e.000f/interruptIf interrupts are used, the attribute shows
Interrupts enabled, otherwise
Interrupts disabled.