sssd: version 2.9.4
i used openLDAP，there is a user named user1. when there are much process running, following command will take much time.
sudo -u user1 ls /tmp
reproduce as following（total about 130 process running）
command：time sudo -u user1 ls /tmp
result：
**real 0m0.027s**
user 0m0.002s
sys 0m0.013s

run shell to creat more process
shell：
for i in `seq 2000`; do
sleep 100 &
done

after more process running，run command again
command：time sudo -u user1 ls /tmp
result：
**real 0m0.087s**
user 0m0.004s
sys 0m0.010s

pam config include：
-session optional pam_sss.so
when i comment that，The problem no longer exists。

following PR intruduced to reading /proc。it take much time enumerating running process to find uid especially when the uid does not exist。
https://github.com/SSSD/sssd/commit/d2424bfb733c4de1582ad423394aa272e109b58a

I'm not quite sure if the issue is caused by the configuration。
Any help would be appreciated！

sssd.conf:
[sssd]
services = nss, pam
domains = LDAP
debug_level = 9

[domain/LDAP]
id_provider = ldap
auth_provider = ldap
chpass_provider = ldap
autofs_provider = ldap
ldap_schema = rfc2307bis
ldap_id_use_start_tls = false
ldap_tls_reqcert = never
enumerate = True
cache_credentials = True
ldap_uri = ldap://xxx:389
ldap_search_base = dc=my-domain,dc=com
timeout = 30
debug_level = 9

[nss]
homedir_substring = /home
enum_cache_timeout = 10
debug_level = 9

[pam]
offline_credentials_expiration = 1
debug_level = 9