openldap client connect limit

[罗志坚 <luozhijian@huawei.com>]

I using directory mark to test openldap.

when I configure dm to start 20 client,50 thread/client,openldap work well. 
when I configure dm to start 21 client,50 thread/client,some dm client connect failed.then I found 
openldap #define LDAP_MAXTHR 1024 in tpool.c,then I modify it to 4096 and recompile,but it didn't work. 

thread exiting do to error: status 1
ldap_simple_bind_s: : Can't contact LDAP server
**********Could not connect as root!
thread exiting do to error: status 1
ldap_simple_bind_s (856200, "cn=Manager,o=huawei.com", secret) returned 0x51
ldap_simple_bind_s: : Can't contact LDAP server
**********Could not connect as root!
thread exiting do to error: status 1
ldap_simple_bind_s (887296, "cn=Manager,o=huawei.com", secret) returned 0x51
ldap_simple_bind_s: : Can't contact LDAP server
**********Could not connect as root!
thread exiting do to error: status 1
ldap_simple_bind_s (894472, "ldap_simple_bind_s (872944cn=Manager,o=huawei.com",
 secret) returned 0x51
ldap_simple_bind_s: : Can't contact LDAP server, "cn=Manager,o=huawei.com
", secret) returned 0x**********Could not connect as root!
51
thread exiting do to error: status 1
ldap_simple_bind_s: : Can't contact LDAP server
**********Could not connect as root!
thread exiting do to error: status 1
ldap_simple_bind_s (884904, "ldap_simple_bind_s (cn=Manager,o=huawei.com875336",
 , "cn=Manager,o=huawei.comsecret", secret) returned 0x) returned 0x51
51
ldap_simple_bind_s: : Can't contact LDAP server
**********Could not connect as root!
ldap_simple_bind_s: : Can't contact LDAP serverthread exiting do to error: statu
s 1

**********Could not connect as root!
thread exiting do to error: status 1
ldap_simple_bind_s (882512, "cn=Manager,o=huawei.com", secret) returned 0x51
ldap_simple_bind_s: : Can't contact LDAP server
**********Could not connect as root!
thread exiting do to error: status 1