On Wed, Aug 18, 2021 at 5:33 AM Yunsheng Lin <linyunsheng@xxxxxxxxxx> wrote:
>
> This patchset adds the socket to netdev page frag recycling
> support based on the busy polling and page pool infrastructure.
I really do not see how this can scale to thousands of sockets.
tcp_mem[] defaults to ~ 9 % of physical memory.
If you now run tests with thousands of sockets, their skbs will
consume Gigabytes
of memory on typical servers, now backed by order-0 pages (instead of
current order-3 pages)
So IOMMU costs will actually be much bigger.
Are we planning to use Gigabyte sized page pools for NIC ?
Have you tried instead to make TCP frags twice bigger ?
This would require less IOMMU mappings.
(Note: This could require some mm help, since PAGE_ALLOC_COSTLY_ORDER
is currently 3, not 4)
diff --git a/net/core/sock.c b/net/core/sock.c
index a3eea6e0b30a7d43793f567ffa526092c03e3546..6b66b51b61be9f198f6f1c4a3d81b57fa327986a
100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2560,7 +2560,7 @@ static void sk_leave_memory_pressure(struct sock *sk)
}
}
-#define SKB_FRAG_PAGE_ORDER get_order(32768)
+#define SKB_FRAG_PAGE_ORDER get_order(65536)
DEFINE_STATIC_KEY_FALSE(net_high_order_alloc_disable_key);
/**
>
> The profermance improve from 30Gbit to 41Gbit for one thread iperf
> tcp flow, and the CPU usages decreases about 20% for four threads
> iperf flow with 100Gb line speed in IOMMU strict mode.
>
> The profermance improve about 2.5% for one thread iperf tcp flow
> in IOMMU passthrough mode.
>
> Yunsheng Lin (7):
> page_pool: refactor the page pool to support multi alloc context
> skbuff: add interface to manipulate frag count for tx recycling
> net: add NAPI api to register and retrieve the page pool ptr
> net: pfrag_pool: add pfrag pool support based on page pool
> sock: support refilling pfrag from pfrag_pool
> net: hns3: support tx recycling in the hns3 driver
> sysctl_tcp_use_pfrag_pool
>
> drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 32 +++++----
> include/linux/netdevice.h | 9 +++
> include/linux/skbuff.h | 43 +++++++++++-
> include/net/netns/ipv4.h | 1 +
> include/net/page_pool.h | 15 ++++
> include/net/pfrag_pool.h | 24 +++++++
> include/net/sock.h | 1 +
> net/core/Makefile | 1 +
> net/core/dev.c | 34 ++++++++-
> net/core/page_pool.c | 86 ++++++++++++-----------
> net/core/pfrag_pool.c | 92 +++++++++++++++++++++++++
> net/core/sock.c | 12 ++++
> net/ipv4/sysctl_net_ipv4.c | 7 ++
> net/ipv4/tcp.c | 34 ++++++---
> 14 files changed, 325 insertions(+), 66 deletions(-)
> create mode 100644 include/net/pfrag_pool.h
> create mode 100644 net/core/pfrag_pool.c
>
> --
> 2.7.4
>
