icmp AddIPAddr ping lots of ip , return unstable

[CentUser]

p.AddIPAddr(ra). I added lots of ra on p perhaps thousands of it.
OnRecv I record the recieved IP and turn on a bool.
p.Run, could return with no error, yet, the recieved is not stable.
While I know Ping is not stable on network, but it should not be too unreliable( I devided the thousands of IPs to 250 a group, and ping them at a time, the result could be more stable).
For my situation, I pinged 10000 IPs, if I ping them using AddIPAddr, I could only get perhaps 1000 IPs alive, But if I change to 250 IPs a group and ping all the 10000 IPs for 40 groups, I could get perhaps 8000 IPs alive.
Does anyone have an idea on this situation?

[zh7606559342012]

i meet the same trouble,unstable results