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Date: Mon, 27 Jun 2022 21:04:01 +0800 From: "wangjie (L)" <wangjie125@...wei.com> To: Jesper Dangaard Brouer <jbrouer@...hat.com>, Guangbin Huang <huangguangbin2@...wei.com>, <hawk@...nel.org>, <ilias.apalodimas@...aro.org>, <davem@...emloft.net>, <kuba@...nel.org>, <edumazet@...gle.com>, <pabeni@...hat.com> CC: <brouer@...hat.com>, <lorenzo@...nel.org>, <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>, <bpf@...r.kernel.org>, <lipeng321@...wei.com>, <chenhao288@...ilicon.com> Subject: Re: [PATCH net-next] net: page_pool: optimize page pool page allocation in NUMA scenario On 2022/6/27 17:50, Jesper Dangaard Brouer wrote: > > > On 24/06/2022 11.36, Guangbin Huang wrote: >> From: Jie Wang <wangjie125@...wei.com> >> >> Currently NIC packet receiving performance based on page pool >> deteriorates >> occasionally. To analysis the causes of this problem page allocation >> stats >> are collected. Here are the stats when NIC rx performance deteriorates: >> >> bandwidth(Gbits/s) 16.8 6.91 >> rx_pp_alloc_fast 13794308 21141869 >> rx_pp_alloc_slow 108625 166481 >> rx_pp_alloc_slow_h 0 0 >> rx_pp_alloc_empty 8192 8192 >> rx_pp_alloc_refill 0 0 >> rx_pp_alloc_waive 100433 158289 >> rx_pp_recycle_cached 0 0 >> rx_pp_recycle_cache_full 0 0 >> rx_pp_recycle_ring 362400 420281 >> rx_pp_recycle_ring_full 6064893 9709724 >> rx_pp_recycle_released_ref 0 0 >> >> The rx_pp_alloc_waive count indicates that a large number of pages' numa >> node are inconsistent with the NIC device numa node. Therefore these >> pages >> can't be reused by the page pool. As a result, many new pages would be >> allocated by __page_pool_alloc_pages_slow which is time consuming. This >> causes the NIC rx performance fluctuations. >> >> The main reason of huge numa mismatch pages in page pool is that page >> pool >> uses alloc_pages_bulk_array to allocate original pages. This function is >> not suitable for page allocation in NUMA scenario. So this patch uses >> alloc_pages_bulk_array_node which has a NUMA id input parameter to ensure >> the NUMA consistent between NIC device and allocated pages. >> >> Repeated NIC rx performance tests are performed 40 times. NIC rx >> bandwidth >> is higher and more stable compared to the datas above. Here are three >> test >> stats, the rx_pp_alloc_waive count is zero and rx_pp_alloc_slow which >> indicates pages allocated from slow patch is relatively low. >> >> bandwidth(Gbits/s) 93 93.9 93.8 >> rx_pp_alloc_fast 60066264 61266386 60938254 >> rx_pp_alloc_slow 16512 16517 16539 >> rx_pp_alloc_slow_ho 0 0 0 >> rx_pp_alloc_empty 16512 16517 16539 >> rx_pp_alloc_refill 473841 481910 481585 >> rx_pp_alloc_waive 0 0 0 >> rx_pp_recycle_cached 0 0 0 >> rx_pp_recycle_cache_full 0 0 0 >> rx_pp_recycle_ring 29754145 30358243 30194023 >> rx_pp_recycle_ring_full 0 0 0 >> rx_pp_recycle_released_ref 0 0 0 >> >> Signed-off-by: Jie Wang <wangjie125@...wei.com> >> --- >> net/core/page_pool.c | 11 ++++++++++- >> 1 file changed, 10 insertions(+), 1 deletion(-) > > Thanks for improving this, but we need some small adjustments below. > And then you need to send a V2 of the patch. > >> diff --git a/net/core/page_pool.c b/net/core/page_pool.c >> index f18e6e771993..15997fcd78f3 100644 >> --- a/net/core/page_pool.c >> +++ b/net/core/page_pool.c >> @@ -377,6 +377,7 @@ static struct page >> *__page_pool_alloc_pages_slow(struct page_pool *pool, >> unsigned int pp_order = pool->p.order; >> struct page *page; >> int i, nr_pages; >> + int pref_nid; /* preferred NUMA node */ >> /* Don't support bulk alloc for high-order pages */ >> if (unlikely(pp_order)) >> @@ -386,10 +387,18 @@ static struct page >> *__page_pool_alloc_pages_slow(struct page_pool *pool, >> if (unlikely(pool->alloc.count > 0)) >> return pool->alloc.cache[--pool->alloc.count]; >> +#ifdef CONFIG_NUMA >> + pref_nid = (pool->p.nid == NUMA_NO_NODE) ? numa_mem_id() : >> pool->p.nid; >> +#else >> + /* Ignore pool->p.nid setting if !CONFIG_NUMA, helps compiler */ > > Remove "helps compiler" from comments, it only make sense in the code > this was copy-pasted from. > > >> + pref_nid = numa_mem_id(); /* will be zero like page_to_nid() */ > > The comment about "page_to_nid()" is only relevant in the code > this was copy-pasted from. > > Change to: > pref_nid = NUMA_NO_NODE; > > As alloc_pages_bulk_array_node() will be inlined, the effect (generated > asm code) will be the same, but it will be better for code maintenance. > OKļ¼thanks for your review, I will fix it in next version. >> +#endif >> + >> /* Mark empty alloc.cache slots "empty" for >> alloc_pages_bulk_array */ >> memset(&pool->alloc.cache, 0, sizeof(void *) * bulk); >> - nr_pages = alloc_pages_bulk_array(gfp, bulk, pool->alloc.cache); >> + nr_pages = alloc_pages_bulk_array_node(gfp, pref_nid, bulk, >> + pool->alloc.cache); >> if (unlikely(!nr_pages)) >> return NULL; >> > > > . >
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