Re: [PATCH net-next] r8169: Add 64bit statistics

[Eric Dumazet <eric.dumazet@gmail.com>]

Le jeudi 17 novembre 2011 à 15:46 +0800, Junchang Wang a écrit :
> > You dont need per-cpu since Tx is locked by dev->xmit_lock and
> > rx is implicitly single threaded by NAPI.
> 
> Thanks.
> 
> >You do need to have
> > two u64_stat_sync entries (one for Tx and one for Rx).
> 
> You mean Rx and Tx will perform on different cores at one moment.
> So I need a sync for Tx to protect tx_xxx, and another for Rx to
> protect rx_xxx. Is that right?
> 

Yes, look at sky2.c for a template

drivers/net/ethernet/marvell/sky2.c contains code like that
(different syncp for rx/tx)

TX path:
                        u64_stats_update_begin(&sky2->tx_stats.syncp);
                        ++sky2->tx_stats.packets;
                        sky2->tx_stats.bytes += skb->len;
                        u64_stats_update_end(&sky2->tx_stats.syncp);


RX path:

        u64_stats_update_begin(&sky2->rx_stats.syncp);
        sky2->rx_stats.packets += packets;
        sky2->rx_stats.bytes += bytes;
        u64_stats_update_end(&sky2->rx_stats.syncp);