Re: [PATCH net-next v3 6/7] bcm63xx_enet: convert to build_skb

[Florian Fainelli <f.fainelli@gmail.com>]

On 1/6/21 6:42 AM, Sieng Piaw Liew wrote:
> We can increase the efficiency of rx path by using buffers to receive
> packets then build SKBs around them just before passing into the network
> stack. In contrast, preallocating SKBs too early reduces CPU cache
> efficiency.
> 
> Check if we're in NAPI context when refilling RX. Normally we're almost
> always running in NAPI context. Dispatch to napi_alloc_frag directly
> instead of relying on netdev_alloc_frag which does the same but
> with the overhead of local_bh_disable/enable.
> 
> Tested on BCM6328 320 MHz and iperf3 -M 512 to measure packet/sec
> performance. Included netif_receive_skb_list and NET_IP_ALIGN
> optimizations.
> 
> Before:
> [ ID] Interval           Transfer     Bandwidth       Retr
> [  4]   0.00-10.00  sec  49.9 MBytes  41.9 Mbits/sec  197         sender
> [  4]   0.00-10.00  sec  49.3 MBytes  41.3 Mbits/sec            receiver
> 
> After:
> [ ID] Interval           Transfer     Bandwidth       Retr
> [  4]   0.00-30.00  sec   171 MBytes  47.8 Mbits/sec  272         sender
> [  4]   0.00-30.00  sec   170 MBytes  47.6 Mbits/sec            receiver
> 
> Signed-off-by: Sieng Piaw Liew <liew.s.piaw@gmail.com>

Acked-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian