Kirill Korotaev wrote: > Eric W. Biederman wrote: >> Daniel Lezcano <dlezcano@xxxxxxxxxx> writes: >> >> >>> Benjamin Thery and I we were looking at this. >>> For the moment we are investigating if there is IP fragmentation between the >>> eth0 and the pair devices. >>> The profiling shows us "pskb_expand_head" and "csum_partial_copy_generic" >>> functions have the bigger CPU usage when we are inside a container. >> >> Hmm. Interesting hypothesis. I do know I haven't finished the IP fragment >> support so there may be an issue there. Although generally especially with >> TCP fragments are not generated. How are you thinking fragmentation would >> be involved? > > I'm not sure I fully understand the test and details of the thread, > but still... > > if network device inside container has MTU higher then eth0 outside the container, > then packets will get fragmented. > First time to MTU1 inside container and refragmented to MTU2 > outside the container. At least this is the reason we use ethernet MTU > on venet devices in OpenVZ - to avoid framentation. frankly speaking, there are another points, which can call to pskb_expand_head. Hard header size on container network device should be the same as on real one. Regards, Den _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
