| Message ID | 20190526153357.82293-2-fklassen@appneta.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Allow TX timestamp with UDP GSO | expand |
On Sun, May 26, 2019 at 10:37 AM Fred Klassen <fklassen@appneta.com> wrote: > > Fixes an issue where TX Timestamps are not arriving on the error queue > when UDP_SEGMENT CMSG type is combined with CMSG type SO_TIMESTAMPING. > This can be illustrated with an updated updgso_bench_tx program which > includes the '-T' option to test for this condition. > > ./udpgso_bench_tx -4ucTPv -S 1472 -l2 -D 172.16.120.18 > poll timeout > udp tx: 0 MB/s 1 calls/s 1 msg/s > > The "poll timeout" message above indicates that TX timestamp never > arrived. > > It also appears that other TX CMSG types cause similar issues, for > example trying to set SOL_IP/IP_TOS. If correct we need to find the root cause. Without that, this is not very informative. And likely the fix is not related, as that does not involve tx_flags or tskey. What exact behavior do you observe: tx timestamp notifications go missing when enabling IP_TOS? > > ./udpgso_bench_tx -4ucPv -S 1472 -q 182 -l2 -D 172.16.120.18 > poll timeout > udp tx: 0 MB/s 1 calls/s 1 msg/s > > This patch preserves tx_flags for the first UDP GSO segment. This > mirrors the stack's behaviour for IPv4 fragments. But deviates from the established behavior of other transport protocol TCP. I think it's a bit premature to resubmit as is while still discussing the original patch. > > Fixes: ee80d1ebe5ba ("udp: add udp gso") > Signed-off-by: Fred Klassen <fklassen@appneta.com> > --- > net/ipv4/udp_offload.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c > index 065334b41d57..33de347695ae 100644 > --- a/net/ipv4/udp_offload.c > +++ b/net/ipv4/udp_offload.c > @@ -228,6 +228,10 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, > seg = segs; > uh = udp_hdr(seg); > > + /* preserve TX timestamp and zero-copy info for first segment */ As pointed out in v1, zerocopy flags are handled by protocol independent skb_segment. It calls skb_zerocopy_clone. > + skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey; > + skb_shinfo(seg)->tx_flags = skb_shinfo(gso_skb)->tx_flags; > + > /* compute checksum adjustment based on old length versus new */ > newlen = htons(sizeof(*uh) + mss); > check = csum16_add(csum16_sub(uh->check, uh->len), newlen); > -- > 2.11.0 >
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 065334b41d57..33de347695ae 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -228,6 +228,10 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, seg = segs; uh = udp_hdr(seg); + /* preserve TX timestamp and zero-copy info for first segment */ + skb_shinfo(seg)->tskey = skb_shinfo(gso_skb)->tskey; + skb_shinfo(seg)->tx_flags = skb_shinfo(gso_skb)->tx_flags; + /* compute checksum adjustment based on old length versus new */ newlen = htons(sizeof(*uh) + mss); check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
Fixes an issue where TX Timestamps are not arriving on the error queue when UDP_SEGMENT CMSG type is combined with CMSG type SO_TIMESTAMPING. This can be illustrated with an updated updgso_bench_tx program which includes the '-T' option to test for this condition. ./udpgso_bench_tx -4ucTPv -S 1472 -l2 -D 172.16.120.18 poll timeout udp tx: 0 MB/s 1 calls/s 1 msg/s The "poll timeout" message above indicates that TX timestamp never arrived. It also appears that other TX CMSG types cause similar issues, for example trying to set SOL_IP/IP_TOS. ./udpgso_bench_tx -4ucPv -S 1472 -q 182 -l2 -D 172.16.120.18 poll timeout udp tx: 0 MB/s 1 calls/s 1 msg/s This patch preserves tx_flags for the first UDP GSO segment. This mirrors the stack's behaviour for IPv4 fragments. Fixes: ee80d1ebe5ba ("udp: add udp gso") Signed-off-by: Fred Klassen <fklassen@appneta.com> --- net/ipv4/udp_offload.c | 4 ++++ 1 file changed, 4 insertions(+)