executing service (openoffice headless) in chroot is slow

Question

I created an ubuntu chroot environment (using debootstrap) and started openoffice as a service to convert files using unoconv. It works but it spends about 20s to do conversions which are below 1s outside chroot jail. Stracing it I can see that this extra time is spent in some socket operations whose timeout expires, the same operations that work well without a chroot environment. However, similar operations works fine.

Any suggestion?

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starting server (chrooted):

soffice -invisible -headless -nologo -nodefault "-accept=socket,host=localhost,port=8301;urp;StarOffice.ComponentContext" -env:UserInstallation=ootest2

calling it (chrooted too):

strace unoconv -f pdf -p 8300 simple_test.docx

timeout trace:

socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4
connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.1")}, 16) = 0
fcntl(4, F_GETFL)                       = 0x2 (flags O_RDWR)
fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK)    = 0
poll([{fd=4, events=POLLOUT}], 1, 0)    = 1 ([{fd=4, revents=POLLOUT}])
sendto(4, "M#\1\0\0\1\0\0\0\0\0\0\tlocalhost\6(none)\10mo"..., 47, MSG_NOSIGNAL, NULL, 0) = 47
poll([{fd=4, events=POLLIN}], 1, 5000)  = 0 (Timeout)
close(4)                                = 0

similar trace without timeout (same unoconv operation):

socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4
connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.1")}, 16) = 0
fcntl(4, F_GETFL)                       = 0x2 (flags O_RDWR)
fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK)    = 0
poll([{fd=4, events=POLLOUT}], 1, 0)    = 1 ([{fd=4, revents=POLLOUT}])
sendto(4, "M#\1\0\0\1\0\0\0\0\0\0\tlocalhost\6(none)\10mo"..., 47, MSG_NOSIGNAL, NULL, 0) = 47
poll([{fd=4, events=POLLIN}], 1, 5000)  = 1 ([{fd=4, revents=POLLIN}])
ioctl(4, FIONREAD, [47])                = 0
recvfrom(4, "M#\201\202\0\1\0\0\0\0\0\0\tlocalhost\6(none)\10mo"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.1")}, [16]) = 47
close(4)                                = 0

chroot details:

• using dchroot to use it as a normal user

• mounted dev, proc, etc as (fstab):

  /tmp /var/local/chrootest/tmp
  /dev /var/local/chrootest/dev
  /sys /var/local/chrootest/sys
  proc-chroot /var/local/chrootest/proc
  devpts-chroot /var/local/chrootest/dev/pts