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ixgbe: let the xdpdrv work with more than 64 cpus

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Originally, ixgbe driver doesn't allow the mounting of xdpdrv if the
server is equipped with more than 64 cpus online. So it turns out that
the loading of xdpdrv causes the "NOMEM" failure.

Actually, we can adjust the algorithm and then make it work through
mapping the current cpu to some xdp ring with the protect of @tx_lock.

Here are some numbers before/after applying this patch with xdp-example
loaded on the eth0X:

As client (tx path):
                     Before    After
TCP_STREAM send-64   734.14    714.20
TCP_STREAM send-128  1401.91   1395.05
TCP_STREAM send-512  5311.67   5292.84
TCP_STREAM send-1k   9277.40   9356.22 (not stable)
TCP_RR     send-1    22559.75  21844.22
TCP_RR     send-128  23169.54  22725.13
TCP_RR     send-512  21670.91  21412.56

As server (rx path):
                     Before    After
TCP_STREAM send-64   1416.49   1383.12
TCP_STREAM send-128  3141.49   3055.50
TCP_STREAM send-512  9488.73   9487.44
TCP_STREAM send-1k   9491.17   9356.22 (not stable)
TCP_RR     send-1    23617.74  23601.60
...

Notice: the TCP_RR mode is unstable as the official document explains.

I tested many times with different parameters combined through netperf.
Though the result is not that accurate, I cannot see much influence on
this patch. The static key is places on the hot path, but it actually
shouldn't cause a huge regression theoretically.

Co-developed-by: Shujin Li <lishujin@kuaishou.com>
Signed-off-by: Shujin Li <lishujin@kuaishou.com>
Signed-off-by: Jason Xing <xingwanli@kuaishou.com>
Tested-by: Sandeep Penigalapati <sandeep.penigalapati@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jason Xing
2021-09-29 10:56:05 -07:00
committed by David S. Miller
parent a3e4abace5
commit 4fe815850b
5 changed files with 77 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
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@@ -299,7 +299,10 @@ static void ixgbe_cache_ring_register(struct ixgbe_adapter *adapter)
static int ixgbe_xdp_queues(struct ixgbe_adapter *adapter)
{
return adapter->xdp_prog ? nr_cpu_ids : 0;
int queues;
queues = min_t(int, IXGBE_MAX_XDP_QS, nr_cpu_ids);
return adapter->xdp_prog ? queues : 0;
}
#define IXGBE_RSS_64Q_MASK 0x3F
@@ -947,6 +950,7 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
ring->count = adapter->tx_ring_count;
ring->queue_index = xdp_idx;
set_ring_xdp(ring);
spin_lock_init(&ring->tx_lock);
/* assign ring to adapter */
WRITE_ONCE(adapter->xdp_ring[xdp_idx], ring);
@@ -1032,6 +1036,9 @@ static void ixgbe_free_q_vector(struct ixgbe_adapter *adapter, int v_idx)
adapter->q_vector[v_idx] = NULL;
__netif_napi_del(&q_vector->napi);
if (static_key_enabled(&ixgbe_xdp_locking_key))
static_branch_dec(&ixgbe_xdp_locking_key);
/*
* after a call to __netif_napi_del() napi may still be used and
* ixgbe_get_stats64() might access the rings on this vector,