lkml.org 
[lkml]   [2019]   [Dec]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [RFC net-next 0/2] mvpp2: page_pool support
On Tue, Dec 24, 2019 at 10:52 AM Ilias Apalodimas
<ilias.apalodimas@linaro.org> wrote:
>
> On Tue, Dec 24, 2019 at 02:01:01AM +0100, Matteo Croce wrote:
> > This patches change the memory allocator of mvpp2 from the frag allocator to
> > the page_pool API. This change is needed to add later XDP support to mvpp2.
> >
> > The reason I send it as RFC is that with this changeset, mvpp2 performs much
> > more slower. This is the tc drop rate measured with a single flow:
> >
> > stock net-next with frag allocator:
> > rx: 900.7 Mbps 1877 Kpps
> >
> > this patchset with page_pool:
> > rx: 423.5 Mbps 882.3 Kpps
> >
> > This is the perf top when receiving traffic:
> >
> > 27.68% [kernel] [k] __page_pool_clean_page
>
> This seems extremly high on the list.
>
> > 9.79% [kernel] [k] get_page_from_freelist
> > 7.18% [kernel] [k] free_unref_page
> > 4.64% [kernel] [k] build_skb
> > 4.63% [kernel] [k] __netif_receive_skb_core
> > 3.83% [mvpp2] [k] mvpp2_poll
> > 3.64% [kernel] [k] eth_type_trans
> > 3.61% [kernel] [k] kmem_cache_free
> > 3.03% [kernel] [k] kmem_cache_alloc
> > 2.76% [kernel] [k] dev_gro_receive
> > 2.69% [mvpp2] [k] mvpp2_bm_pool_put
> > 2.68% [kernel] [k] page_frag_free
> > 1.83% [kernel] [k] inet_gro_receive
> > 1.74% [kernel] [k] page_pool_alloc_pages
> > 1.70% [kernel] [k] __build_skb
> > 1.47% [kernel] [k] __alloc_pages_nodemask
> > 1.36% [mvpp2] [k] mvpp2_buf_alloc.isra.0
> > 1.29% [kernel] [k] tcf_action_exec
> >
> > I tried Ilias patches for page_pool recycling, I get an improvement
> > to ~1100, but I'm still far than the original allocator.
>
> Can you post the recycling perf for comparison?
>

12.00% [kernel] [k] get_page_from_freelist
9.25% [kernel] [k] free_unref_page
6.83% [kernel] [k] eth_type_trans
5.33% [kernel] [k] __netif_receive_skb_core
4.96% [mvpp2] [k] mvpp2_poll
4.64% [kernel] [k] kmem_cache_free
4.06% [kernel] [k] __xdp_return
3.60% [kernel] [k] kmem_cache_alloc
3.31% [kernel] [k] dev_gro_receive
3.29% [kernel] [k] __page_pool_clean_page
3.25% [mvpp2] [k] mvpp2_bm_pool_put
2.73% [kernel] [k] __page_pool_put_page
2.33% [kernel] [k] __alloc_pages_nodemask
2.33% [kernel] [k] inet_gro_receive
2.05% [kernel] [k] __build_skb
1.95% [kernel] [k] build_skb
1.89% [cls_matchall] [k] mall_classify
1.83% [kernel] [k] page_pool_alloc_pages
1.80% [kernel] [k] tcf_action_exec
1.70% [mvpp2] [k] mvpp2_buf_alloc.isra.0
1.63% [kernel] [k] free_unref_page_prepare.part.0
1.45% [kernel] [k] page_pool_return_skb_page
1.42% [act_gact] [k] tcf_gact_act
1.16% [kernel] [k] netif_receive_skb_list_internal
1.08% [kernel] [k] kfree_skb
1.07% [kernel] [k] skb_release_data


> >
> > Any idea on why I get such bad numbers?
>
> Nop but it's indeed strange
>
> >
> > Another reason to send it as RFC is that I'm not fully convinced on how to
> > use the page_pool given the HW limitation of the BM.
>
> I'll have a look right after holidays
>

Thanks

> >
> > The driver currently uses, for every CPU, a page_pool for short packets and
> > another for long ones. The driver also has 4 rx queue per port, so every
> > RXQ #1 will share the short and long page pools of CPU #1.
> >
>
> I am not sure i am following the hardware config here
>

Never mind, it's quite a mess, I needed a lot of time to get it :)

The HW put the packets in different buffer pools depending on the size:
short: 64..128
long: 128..1664
jumbo: 1664..9856

Let's skip the jumbo buffer for now and assume we have 4 CPU, the
driver allocates 4 short and 4 long buffers.
Each port has 4 RX queues, and each one uses a short and a long buffer.
With the page_pool api, we have 8 struct page_pool, 4 for the short
and 4 for the long buffers.


> > This means that for every RX queue I call xdp_rxq_info_reg_mem_model() twice,
> > on two different page_pool, can this be a problem?
> >
> > As usual, ideas are welcome.
> >
> > Matteo Croce (2):
> > mvpp2: use page_pool allocator
> > mvpp2: memory accounting
> >
> > drivers/net/ethernet/marvell/Kconfig | 1 +
> > drivers/net/ethernet/marvell/mvpp2/mvpp2.h | 7 +
> > .../net/ethernet/marvell/mvpp2/mvpp2_main.c | 142 +++++++++++++++---
> > 3 files changed, 125 insertions(+), 25 deletions(-)
> >
> > --
> > 2.24.1
> >
> Cheers
> /Ilias
>

Bye,
--
Matteo Croce
per aspera ad upstream

\
 
 \ /
  Last update: 2019-12-24 14:35    [W:0.055 / U:0.056 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site