The backfire driver reads a numerical string that is sent to the /dev/backfire device and sends the corresponding signal to the calling user program. Reading from /dev/backfire returns the time of the day when the most recent sent request was serviced or 0, if a sent request was not yet received. The time of the day is displayed in seconds since 1970-01-01 00:00:00 UTC followed by the fraction of the second in microseconds separated by a comma.
The backfire driver is normally used in combination with the program sendme to benchmark the performance of the kernel's signal sending capabilities.
head -1 /dev/backfire 0,0 trap "echo Got signal 7" 7 echo 7 >/dev/backfire Got signal 7 head -1 /dev/backfire 1234567890,123456
Carsten Emde <[email protected]>