1.
Dprocess on SMP
Siyuan Ma

2. Arch
Ft process
User console
Ft event queue
Ft daemon
Ft_kthread_queue

3. Ft daemon Ft daemon Ft event queue sync error compare error socket
period
event
sync
error
sync error handler
compare error handler
period event handler
Kill the error process
Check ft queue
close the ft mode
Tell the console
Report to console
Tell the console
fork a new twin
log

4. Ft daemon
cons
central fault handler make it easy to change the ft policy
do not affect the running of ft processes even if it is down
pros
Single Point of Failure
more centralization, less fault tolerance
able to improve
sort the event queue before handler it, more analysis
More option in console
Periodic reboot to overcome the Single Point of Failure

5. User process breakdown
Code Seg 1
Sync 1
Code Seg 2
Sync 2
Code Seg 3
Sync 3
Process X
Code Seg 1
Sync 1
Code Seg 2
Sync 2
Code Seg 3
Sync 3
Process X’
Sync
sleep on a queue to wait brother
add a timer
timer
Sync?
Time out?
Sync
FT Daemon
User process moniter
Reboot abnormal process
remove the timer
Wake up the brother
Brother gone?

6. Recovery process x process x’ process x’’ Ft daemon handler sync
killed by daemon
double fork
process x
sync
timeout
sync
sync
exit
wake up
process x’
fork by process 2
exit
process x’’
Ft daemon
handler