Issue 6993: importing of "time" module is terribly slow (original) (raw)

The behaviour described below is not always reproduced.

The attached test script simply tries to import a couple of dns-python modules, which in turn import other ones. No code is being executed. You expect it to exit for less than a second but it does not. Instead, it hangs when "time" module is being imported (eventually it exits after a long time).

Attached are stdout log and system call log produced by strace with timestamps.

I don't know what causes it but I'm getting it on at least two machines (the second being virtual):

$ cat /etc/fedora-release Fedora release 10 (Cambridge) $ uname -a Linux kiki 2.6.27.30-170.2.82.fc10.i686.PAE #1 SMP Mon Aug 17 08:24:23 EDT 2009 i686 i686 i386 GNU/Linux $ python -c "import sys; print sys.version" 2.5.2 (r252:60911, Sep 30 2008, 15:41:38) [GCC 4.3.2 20080917 (Red Hat 4.3.2-4)]

$ cat /etc/redhat-release CentOS release 5.3 (Final) $ uname -a Linux proxy.sc.com 2.6.18-128.el5 #1 SMP Wed Jan 21 10:44:23 EST 2009 i686 i686 i386 GNU/Linux $ python -c "import sys; print sys.version" 2.4.3 (#1, Jan 21 2009, 01:10:13) [GCC 4.1.2 20071124 (Red Hat 4.1.2-42)]

I don't think it's related to dns-python(that's why I am posting it here) but for reference the version used is 1.7.1.

The timestamps in stdout.log and strace.log clearly show the slowdown:

strace.log

18🔞53 ioctl(6, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbfac06b0) = -1 EINVAL (Invalid argument) 18🔞53 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7e4f000 18🔞53 read(6, "F\t\262\276\261s\223I"..., 4096) = 8 18:19:01 read(6, ")v\244\36\v=U\336"..., 4096) = 8 18:19:11 close(6) = 0 18:19:11 munmap(0xb7e4f000, 4096) = 0 18:19:11 gettimeofday({1253891951, 431529}, NULL) = 0

stdout.log

18🔞53 dns.entropy 18🔞53 time 18:19:11 hashlib 18:19:11 _hashlib