Messages in this thread | | | From | Jesper Dangaard Brouer <> | Date | Mon, 27 Jun 2022 11:50:44 +0200 | Subject | Re: [PATCH net-next] net: page_pool: optimize page pool page allocation in NUMA scenario |
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On 24/06/2022 11.36, Guangbin Huang wrote: > From: Jie Wang <wangjie125@huawei.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@huawei.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.
> +#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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