Description of problem:
Bad scalability with memory cgroups.
Version-Release number of selected component (if applicable):
run a program that allocates memory on a 32 cpu system
Steps to Reproduce:
1. create a user Memory Cgroup
2. run 32 occurences of program that allocates memory
3. compare time with same program executed outside Memory cgroup or with cgroup_disable=memory
. in cgroup memory:
Time for Allocating Buffers : 100.222279 second(s)
75.70% _spin_lock res_counter_uncharge
. outside cgroup memory:
Time for Allocating Buffers : 3.721997 second(s)
perf profiling shows contention on cgroup spinlock. This has been reworked in recent kernels to coalesce the accounting on cgroup. 2.6.37 kernel does not show the problem of scalability.
75.70% malloc_seq [kernel.kallsyms] [k] _s
| |--100.00%-- exit_mm
| | do_exit
| | do_group_exit
| | sys_exit_group
| | system_call_fastpath
| --0.00%-- [...]
Is this the same issue as reported from Bull via myself at:
Yes,....Sorry I missed it was already opened as a Bugzilla.
No problem. I'll closed this BZ as a DUPLICATE of the other.
Can I ask you to please add the above information (and any additional data) as a new comment on the other BZ? (so that it is seen to come from an @bull.net address rather than an internal @redhat.com address).
*** This bug has been marked as a duplicate of bug 717803 ***