Re: [PATCH net-next RFC 0/2] add elevated refcnt support for page pool

[Matteo Croce]

On Wed, Jul 7, 2021 at 6:50 PM Marcin Wojtas <mw@xxxxxxxxxxxx> wrote:
>
> Hi,
>
>
> śr., 7 lip 2021 o 01:20 Matteo Croce <mcroce@xxxxxxxxxxxxxxxxxxx> napisał(a):
> >
> > On Tue, Jul 6, 2021 at 5:51 PM Russell King (Oracle)
> > <linux@xxxxxxxxxxxxxxx> wrote:
> > >
> > > On Fri, Jul 02, 2021 at 03:39:47PM +0200, Matteo Croce wrote:
> > > > On Wed, 30 Jun 2021 17:17:54 +0800
> > > > Yunsheng Lin <linyunsheng@xxxxxxxxxx> wrote:
> > > >
> > > > > This patchset adds elevated refcnt support for page pool
> > > > > and enable skb's page frag recycling based on page pool
> > > > > in hns3 drvier.
> > > > >
> > > > > Yunsheng Lin (2):
> > > > >   page_pool: add page recycling support based on elevated refcnt
> > > > >   net: hns3: support skb's frag page recycling based on page pool
> > > > >
> > > > >  drivers/net/ethernet/hisilicon/hns3/hns3_enet.c    |  79 +++++++-
> > > > >  drivers/net/ethernet/hisilicon/hns3/hns3_enet.h    |   3 +
> > > > >  drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c |   1 +
> > > > >  drivers/net/ethernet/marvell/mvneta.c              |   6 +-
> > > > >  drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c    |   2 +-
> > > > >  include/linux/mm_types.h                           |   2 +-
> > > > >  include/linux/skbuff.h                             |   4 +-
> > > > >  include/net/page_pool.h                            |  30 ++-
> > > > >  net/core/page_pool.c                               | 215
> > > > > +++++++++++++++++---- 9 files changed, 285 insertions(+), 57
> > > > > deletions(-)
> > > > >
> > > >
> > > > Interesting!
> > > > Unfortunately I'll not have access to my macchiatobin anytime soon, can
> > > > someone test the impact, if any, on mvpp2?
> > >
> > > I'll try to test. Please let me know what kind of testing you're
> > > looking for (I haven't been following these patches, sorry.)
> > >
> >
> > A drop test or L2 routing will be enough.
> > BTW I should have the macchiatobin back on friday.
>
> I have a 10G packet generator connected to 10G ports of CN913x-DB - I
> will stress mvpp2 in l2 forwarding early next week (I'm mostly AFK
> this until Monday).
>

I managed to to a drop test on mvpp2. Maybe there is a slowdown but
it's below the measurement uncertainty.

Perf top before:

Overhead  Shared O  Symbol
   8.48%  [kernel]  [k] page_pool_put_page
   2.57%  [kernel]  [k] page_pool_refill_alloc_cache
   1.58%  [kernel]  [k] page_pool_alloc_pages
   0.75%  [kernel]  [k] page_pool_return_skb_page

after:

Overhead  Shared O  Symbol
   8.34%  [kernel]  [k] page_pool_put_page
   4.52%  [kernel]  [k] page_pool_return_skb_page
   4.42%  [kernel]  [k] page_pool_sub_bias
   3.16%  [kernel]  [k] page_pool_alloc_pages
   2.43%  [kernel]  [k] page_pool_refill_alloc_cache

Regards,
-- 
per aspera ad upstream