Re: [PATCH net-next RFC 0/2] add elevated refcnt support for page pool
From: Yunsheng Lin <hidden>
Date: 2021-07-09 06:40:21
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On 2021/7/9 12:15, Matteo Croce wrote:
On Wed, Jul 7, 2021 at 6:50 PM Marcin Wojtas [off-list ref] wrote:quoted
Hi, śr., 7 lip 2021 o 01:20 Matteo Croce [off-list ref] napisał(a):quoted
On Tue, Jul 6, 2021 at 5:51 PM Russell King (Oracle) [off-list ref] wrote:quoted
On Fri, Jul 02, 2021 at 03:39:47PM +0200, Matteo Croce wrote:quoted
On Wed, 30 Jun 2021 17:17:54 +0800 Yunsheng Lin [off-list ref] wrote:quoted
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
Hi, Matteo Thanks for the testing. it seems you have adapted the mvpp2 driver to use the new frag API for page pool, There is one missing optimization for XDP case, the page is always returned to the pool->ring regardless of the context of page_pool_put_page() for elevated refcnt case. Maybe adding back that optimization will close some gap of the above performance difference if the drop is happening in softirq context.
Regards,