I have perl base SIP client which calling for SIP REGISTRATION process but i am seeing it stall for 10 second at nanosleep() call send(4, REGISTER sip:sip.example.com S..., 513, 0) = 513select(8, [4], NULL, NULL, {15, 0})     = 1 (in [4], left {14, 999000})recvfrom(4, SIP/2.0 401 Unauthorized\r\nVia: S..., 1000, 0, {sa_family=AF_INET, sin_port=htons(6250), sin_addr=inet_addr(24.37.100.2)}, [16]) = 402time(NULL)                              = 1457025606time(NULL)                              = 1457025606send(4, REGISTER sip:sip.example.com S..., 679, 0) = 679select(8, [4], NULL, NULL, {15, 0})     = 1 (in [4], left {15, 0})recvfrom(4, SIP/2.0 401 Unauthorized\r\nVia: S..., 1000, 0, {sa_family=AF_INET, sin_port=htons(6250), sin_addr=inet_addr(24.37.100.2)}, [16]) = 402time(NULL)                              = 1457025606rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0nanosleep({10, 0}, {10, 0})             = 0time(NULL) Any idea what is going on? Linux kerner version is 2.6.18-371.12.1.el5 CentOS 5.x
perl script stall nanosleep() call in strace output
linux;kernel;perl;system calls