Messages in this thread Patch in this message | | | Date | Mon, 20 Nov 2023 11:55:46 +0100 | From | Lorenzo Bianconi <> | Subject | Re: [External] Re: [PATCH net] veth: fix ethtool statistical errors |
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> Lorenzo Bianconi <lorenzo@kernel.org> 于2023年11月20日周一 17:52写道: > > > > > Lorenzo Bianconi <lorenzo@kernel.org> 于2023年11月17日周五 17:26写道: > > > > > > > > > if peer->real_num_rx_queues > 1, the ethtool -s command for > > > > > veth network device will display some error statistical values. > > > > > The value of tx_idx is reset with each iteration, so even if > > > > > peer->real_num_rx_queues is greater than 1, the value of tx_idx > > > > > will remain constant. This results in incorrect statistical values. > > > > > To fix this issue, assign the value of pp_idx to tx_idx. > > > > > > > > > > Fixes: 5fe6e56776ba ("veth: rely on peer veth_rq for ndo_xdp_xmit accounting") > > > > > Signed-off-by: Albert Huang <huangjie.albert@bytedance.com> > > > > > --- > > > > > drivers/net/veth.c | 2 +- > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > diff --git a/drivers/net/veth.c b/drivers/net/veth.c > > > > > index 0deefd1573cf..3a8e3fc5eeb5 100644 > > > > > --- a/drivers/net/veth.c > > > > > +++ b/drivers/net/veth.c > > > > > @@ -225,7 +225,7 @@ static void veth_get_ethtool_stats(struct net_device *dev, > > > > > for (i = 0; i < peer->real_num_rx_queues; i++) { > > > > > const struct veth_rq_stats *rq_stats = &rcv_priv->rq[i].stats; > > > > > const void *base = (void *)&rq_stats->vs; > > > > > - unsigned int start, tx_idx = idx; > > > > > + unsigned int start, tx_idx = pp_idx; > > > > > size_t offset; > > > > > > > > > > tx_idx += (i % dev->real_num_tx_queues) * VETH_TQ_STATS_LEN; > > > > > -- > > > > > 2.20.1 > > > > > > > > > > > > > Hi Albert, > > > > > > > > Can you please provide more details about the issue you are facing? > > > > In particular, what is the number of configured tx and rx queues for both > > > > peers? > > > > > > Hi, Lorenzo > > > I found this because I wanted to add more echo information in ethttool(for veth, > > > but I found that the information was incorrect. That's why I paid > > > attention here. > > > > ack. Could you please share the veth pair tx/rx queue configuration? > > > > dev: tx --->4. rx--->4 > peer: tx--->1 rx---->1 > > Could the following code still be problematic? pp_idx not updated correctly. > page_pool_stats: > veth_get_page_pool_stats(dev, &data[pp_idx]);
Thx for pointing this out. This part is a bit tricky but I think I can see the issue now. Since we have just one peer rx queue, when we run ndo_xdp_xmit pointer on dev, we will squash all dev xmit queues on the single peer rx one (where we do do the accounting) [0]. The issue is ethtool will display all dev xmit queues so we need to set pp_idx properly in veth_get_ethtool_stats(). Can you please take a look to the patch below?
Regards, Lorenzo
[0] https://github.com/LorenzoBianconi/net-next/blob/master/drivers/net/veth.c#L417
diff --git a/drivers/net/veth.c b/drivers/net/veth.c index 9980517ed8b0..8607eb8cf458 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -236,8 +236,8 @@ static void veth_get_ethtool_stats(struct net_device *dev, data[tx_idx + j] += *(u64 *)(base + offset); } } while (u64_stats_fetch_retry(&rq_stats->syncp, start)); - pp_idx = tx_idx + VETH_TQ_STATS_LEN; } + pp_idx = idx + dev->real_num_tx_queues * VETH_TQ_STATS_LEN; page_pool_stats: veth_get_page_pool_stats(dev, &data[pp_idx]); > > BR > Albert > > > Rergards, > > Lorenzo > > > > > > > > > tx_idx is the index of the current (local) tx queue and it must restart from > > > > idx in each iteration otherwise we will have an issue when > > > > peer->real_num_rx_queues is greater than dev->real_num_tx_queues. > > > > > > > OK. I don't know if this is a known issue. > > > > > > BR > > > Albert > > > > > > > > > > Regards, > > > > Lorenzo [unhandled content-type:application/pgp-signature] | |