Re: [PATCH 13/14] mm: memcontrol: account socket memory in unified hierarchy memory controller

Michal Hocko
2015-11-19T13:50:29Z

On Wed 18-11-15 16:48:22, Johannes Weiner wrote:
[...]
> So I ran perf record -g -a netperf -t TCP_STREAM multiple times inside
> a memory-controlled cgroup, but mostly mem_cgroup_charge_skmem() does
> not show up in the profile at all. Once it was there with 0.00%.

OK, this sounds very good! This means that most workloads which are not
focusing solely on the network traffic shouldn't even notice. I can
imagine that workloads with high throughput demands would notice but I
would also expect them to disable the feature.

Could you add this information to the changelog, please?

> I ran another test that downloads the latest kernel image from
> kernel.org at 13MB/s (on my i5 laptop) and it looks like this:
>
> 0.02% 0.01% irq/44-iwlwifi [kernel.kallsyms] [k] mem_cgroup_charge_skmem
> |
> ---mem_cgroup_charge_skmem
> __sk_mem_schedule
> tcp_try_rmem_schedule
> tcp_data_queue
> tcp_rcv_established
> tcp_v4_do_rcv
> tcp_v4_rcv
> ip_local_deliver
> ip_rcv
> __netif_receive_skb_core
> __netif_receive_skb
> netif_receive_skb_internal
> napi_gro_complete
>
> The runs vary too much for this to be measurable in elapsed time.

--
Michal Hocko
SUSE Labs