Hello Zdenek, I got your point, thank you for your explanation. On 12/10/19 5:03 PM, Zdenek Kabelac wrote: > Dne 10. 12. 19 v 4:23 Heming Zhao napsal(a): >> Hello Zdenek, >> >> Thank you for your feedback. >> When I switched to ramdisk backend devices, the time consuming is about 9s. >> >> I raised this topic for there may have a bug in timeout related codes, >> not for why the snapshot-merge.sh costs too much time. >> >> The code in below overwrite silent_start when select() successfully return. >> ``` >> if ( select( nfds, &set, NULL, NULL, &wait ) > 0 ) { >> silent_start = end; /* something happened */ <====== this line! >> io.sync( false ); >> } >> ``` > > Hi > > This is intentional - the idea of this 'timeout' is - that during the timeout period there is no progress on output (i.e. for 180s there was nothing printed - which likely means something got locked - there is also secondary limitation > on number of output lines - so if something is doing endless printing loop, > it's also catched before it fill all disk spaces on testing machine... - hopefully this explains 'something happened' comment. > > In general we don't have strict 'limit' for test length in time - although if test takes 10 minutes - it's likely not what was intended - but we don't have that rule on individual test time as speed often largely depends on machine performance. > > Zdenek > _______________________________________________ linux-lvm mailing list linux-lvm@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/