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mvneta: add XDP ethtool errors stats for TX to driver

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Adding ethtool stats for when XDP transmitted packets overrun the TX
queue. This is recorded separately for XDP_TX and ndo_xdp_xmit. This
is an important aid for troubleshooting XDP based setups.

It is currently a known weakness and property of XDP that there isn't
any push-back or congestion feedback when transmitting frames via XDP.
It's easy to realise when redirecting from a higher speed link into a
slower speed link, or simply two ingress links into a single egress.
The situation can also happen when Ethernet flow control is active.

For testing the patch and provoking the situation to occur on my
Espressobin board, I configured the TX-queue to be smaller (434) than
RX-queue (512) and overload network with large MTU size frames (as a
larger frame takes longer to transmit).

Hopefully the upcoming XDP TX hook can be extended to provide insight
into these TX queue overflows, to allow programmable adaptation
strategies.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jesper Dangaard Brouer 2020-03-02 14:46:28 +01:00 committed by David S. Miller
parent 0b56a29f70
commit 15070919f8
1 changed files with 26 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/net/ethernet/marvell/mvneta.c
View File

@ -344,8 +344,10 @@ enum {
ETHTOOL_XDP_REDIRECT,
ETHTOOL_XDP_PASS,
ETHTOOL_XDP_DROP,
ETHTOOL_XDP_XMIT,
ETHTOOL_XDP_TX,
ETHTOOL_XDP_TX_ERR,
ETHTOOL_XDP_XMIT,
ETHTOOL_XDP_XMIT_ERR,
ETHTOOL_MAX_STATS,
};
@ -404,7 +406,9 @@ static const struct mvneta_statistic mvneta_statistics[] = {
{ ETHTOOL_XDP_PASS, T_SW, "rx_xdp_pass", },
{ ETHTOOL_XDP_DROP, T_SW, "rx_xdp_drop", },
{ ETHTOOL_XDP_TX, T_SW, "rx_xdp_tx", },
{ ETHTOOL_XDP_TX_ERR, T_SW, "rx_xdp_tx_errors", },
{ ETHTOOL_XDP_XMIT, T_SW, "tx_xdp_xmit", },
{ ETHTOOL_XDP_XMIT_ERR, T_SW, "tx_xdp_xmit_errors", },
};
struct mvneta_stats {
@ -417,7 +421,9 @@ struct mvneta_stats {
u64 xdp_pass;
u64 xdp_drop;
u64 xdp_xmit;
u64 xdp_xmit_err;
u64 xdp_tx;
u64 xdp_tx_err;
};
struct mvneta_ethtool_stats {
@ -2059,6 +2065,7 @@ mvneta_xdp_submit_frame(struct mvneta_port *pp, struct mvneta_tx_queue *txq,
static int
mvneta_xdp_xmit_back(struct mvneta_port *pp, struct xdp_buff *xdp)
{
struct mvneta_pcpu_stats *stats = this_cpu_ptr(pp->stats);
struct mvneta_tx_queue *txq;
struct netdev_queue *nq;
struct xdp_frame *xdpf;
@ -2076,8 +2083,6 @@ mvneta_xdp_xmit_back(struct mvneta_port *pp, struct xdp_buff *xdp)
__netif_tx_lock(nq, cpu);
ret = mvneta_xdp_submit_frame(pp, txq, xdpf, false);
if (ret == MVNETA_XDP_TX) {
struct mvneta_pcpu_stats *stats = this_cpu_ptr(pp->stats);
u64_stats_update_begin(&stats->syncp);
stats->es.ps.tx_bytes += xdpf->len;
stats->es.ps.tx_packets++;
@ -2085,6 +2090,10 @@ mvneta_xdp_xmit_back(struct mvneta_port *pp, struct xdp_buff *xdp)
u64_stats_update_end(&stats->syncp);
mvneta_txq_pend_desc_add(pp, txq, 0);
} else {
u64_stats_update_begin(&stats->syncp);
stats->es.ps.xdp_tx_err++;
u64_stats_update_end(&stats->syncp);
}
__netif_tx_unlock(nq);
@ -2128,6 +2137,7 @@ mvneta_xdp_xmit(struct net_device *dev, int num_frame,
stats->es.ps.tx_bytes += nxmit_byte;
stats->es.ps.tx_packets += nxmit;
stats->es.ps.xdp_xmit += nxmit;
stats->es.ps.xdp_xmit_err += num_frame - nxmit;
u64_stats_update_end(&stats->syncp);
return nxmit;
@ -2152,7 +2162,7 @@ mvneta_run_xdp(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
int err;
err = xdp_do_redirect(pp->dev, xdp, prog);
if (err) {
if (unlikely(err)) {
ret = MVNETA_XDP_DROPPED;
page_pool_put_page(rxq->page_pool,
virt_to_head_page(xdp->data), len,
@ -4518,6 +4528,8 @@ mvneta_ethtool_update_pcpu_stats(struct mvneta_port *pp,
u64 skb_alloc_error;
u64 refill_error;
u64 xdp_redirect;
u64 xdp_xmit_err;
u64 xdp_tx_err;
u64 xdp_pass;
u64 xdp_drop;
u64 xdp_xmit;
@ -4532,7 +4544,9 @@ mvneta_ethtool_update_pcpu_stats(struct mvneta_port *pp,
xdp_pass = stats->es.ps.xdp_pass;
xdp_drop = stats->es.ps.xdp_drop;
xdp_xmit = stats->es.ps.xdp_xmit;
xdp_xmit_err = stats->es.ps.xdp_xmit_err;
xdp_tx = stats->es.ps.xdp_tx;
xdp_tx_err = stats->es.ps.xdp_tx_err;
} while (u64_stats_fetch_retry_irq(&stats->syncp, start));
es->skb_alloc_error += skb_alloc_error;
@ -4541,7 +4555,9 @@ mvneta_ethtool_update_pcpu_stats(struct mvneta_port *pp,
es->ps.xdp_pass += xdp_pass;
es->ps.xdp_drop += xdp_drop;
es->ps.xdp_xmit += xdp_xmit;
es->ps.xdp_xmit_err += xdp_xmit_err;
es->ps.xdp_tx += xdp_tx;
es->ps.xdp_tx_err += xdp_tx_err;
}
}
@ -4594,9 +4610,15 @@ static void mvneta_ethtool_update_stats(struct mvneta_port *pp)
case ETHTOOL_XDP_TX:
pp->ethtool_stats[i] = stats.ps.xdp_tx;
break;
case ETHTOOL_XDP_TX_ERR:
pp->ethtool_stats[i] = stats.ps.xdp_tx_err;
break;
case ETHTOOL_XDP_XMIT:
pp->ethtool_stats[i] = stats.ps.xdp_xmit;
break;
case ETHTOOL_XDP_XMIT_ERR:
pp->ethtool_stats[i] = stats.ps.xdp_xmit_err;
break;
}
break;
}