On OpenVZ 7 servers, using prlctl is sensibly slower than using the
similar command with vzctl/vzlist.
For example, on a server with 28 running containers, it takes always
around 0.9seconds to do a "prlctl list" while it takes less than 0.02s
to do a "vzlist".
Doing a "prlctl/vzctl exec /bin/echo" takes 0.2s with prlctl and 0.02s
with vzctl on the same container.
Using strace, the top 5 syscalls by time elapsed with "prlctl exec" :
0.05user 0.04system 0:00.24elapsed 41%CPU (0avgtext+0avgdata
16084maxresident)k
0inputs+0outputs (0major+4202minor)pagefaults 0swaps
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
25.47 0.049546 300 165 11 futex
22.68 0.044114 1225 36 poll
22.49 0.043752 43752 1 wait4
15.16 0.029495 301 98 2 read
7.99 0.015546 273 57 ppoll
Same with "vzctl exec" :
0.00user 0.01system 0:00.03elapsed 59%CPU (0avgtext+0avgdata
3568maxresident)k
0inputs+0outputs (0major+1696minor)pagefaults 0swaps
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
72.76 0.020719 6906 3 wait4
4.46 0.001270 9 149 mmap
3.90 0.001111 10 111 10 open
3.60 0.001025 8 128 write
3.21 0.000913 11 84 read
I have the same issue on every OpenVZ 7 servers i tested with vzctl
"v.7.0.188-1.vz7", prlctl "7.0.153" and a "3.10.0-862.11.6.vz7.64.7" kernel.
Is it a known bug or limitation? should i fill a bug report about it?
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