| Message ID | 20170412141737.5881-7-mlichvar@redhat.com |
|---|---|
| State | RFC, archived |
| Delegated to: | David Miller |
| Headers | show |
On Wed, Apr 12, 2017 at 10:17 AM, Miroslav Lichvar <mlichvar@redhat.com> wrote: > Add SOF_TIMESTAMPING_OPT_MULTIMSG option to allow looping the outgoing > packet to the socket's error queue with a software timestamp even when > a hardware transmit timestamp is expected to be provided by the driver. > > Applications using this option will receive two separate messages from > the error queue, one with a software timestamp and the other with a > hardware timestamp. As the hardware timestamp is saved to the shared skb > info, which may happen before the first message with software timestamp > is received by the application, the hardware timestamp is copied to the > SCM_TIMESTAMPING control message only when the skb has no software > timestamp. > > CC: Richard Cochran <richardcochran@gmail.com> > CC: Willem de Bruijn <willemb@google.com> > Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com> > --- > Documentation/networking/timestamping.txt | 12 ++++++++++-- > include/linux/skbuff.h | 3 +-- > include/uapi/linux/net_tstamp.h | 3 ++- > net/core/skbuff.c | 4 ++++ > net/socket.c | 6 ++++++ > 5 files changed, 23 insertions(+), 5 deletions(-) > > diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt > index ed04aaa..8f30385 100644 > --- a/Documentation/networking/timestamping.txt > +++ b/Documentation/networking/timestamping.txt > @@ -201,6 +201,12 @@ SOF_TIMESTAMPING_OPT_PKTINFO: > this information, it will be attached in struct scm_ts_pktinfo as > a separate control message of type SCM_TIMESTAMPING_PKTINFO. > > +SOF_TIMESTAMPING_OPT_MULTIMSG: > + > + Allow outgoing packets to be looped multiple times to the socket's > + error queue in order to receive both software and hardware transmit > + timestamps. > + It is already possible to receive multiple copies of the same message. Timestamps of type SCM_TSTAMP_SCHED will be passed for every device, virtual or physical, such as bonding. With TCP retransmits, multiple SCM_TSTAMP_SND can be observed. The name for this option is therefore not very descriptive. Perhaps SOF_TIMESTAMPING_OPT_BOTH_SW_HW. > New applications are encouraged to pass SOF_TIMESTAMPING_OPT_ID to > disambiguate timestamps and SOF_TIMESTAMPING_OPT_TSONLY to operate > regardless of the setting of sysctl net.core.tstamp_allow_data. > @@ -320,8 +326,10 @@ struct scm_timestamping { > }; > > The structure can return up to three timestamps. This is a legacy > -feature. Only one field is non-zero at any time. Most timestamps > -are passed in ts[0]. Hardware timestamps are passed in ts[2]. > +feature. Most timestamps are passed in ts[0]. Hardware timestamps > +are passed in ts[2]. Incoming packets may have timestamps in both > +ts[0] and ts[2], but for outgoing packets only one field is non-zero > +at any time. > > ts[1] used to hold hardware timestamps converted to system time. > Instead, expose the hardware clock device on the NIC directly as > diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h > index e91685a..0387c4b 100644 > --- a/include/linux/skbuff.h > +++ b/include/linux/skbuff.h > @@ -3302,8 +3302,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb, > > static inline void sw_tx_timestamp(struct sk_buff *skb) > { > - if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP && > - !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)) > + if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP) > skb_tstamp_tx(skb, NULL); > } > > diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h > index 8397ecd..887e3ff 100644 > --- a/include/uapi/linux/net_tstamp.h > +++ b/include/uapi/linux/net_tstamp.h > @@ -27,8 +27,9 @@ enum { > SOF_TIMESTAMPING_OPT_TSONLY = (1<<11), > SOF_TIMESTAMPING_OPT_STATS = (1<<12), > SOF_TIMESTAMPING_OPT_PKTINFO = (1<<13), > + SOF_TIMESTAMPING_OPT_MULTIMSG = (1<<14), > > - SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_PKTINFO, > + SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_MULTIMSG, > SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) | > SOF_TIMESTAMPING_LAST > }; > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index 7ca251f..d3df8ff 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -3863,6 +3863,10 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb, > if (!sk) > return; > > + if (!hwtstamps && !(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_MULTIMSG) && > + skb_shinfo(orig_skb)->tx_flags & SKBTX_IN_PROGRESS) > + return; > + > tsonly = sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TSONLY; > if (!skb_may_tx_timestamp(sk, tsonly)) > return; > diff --git a/net/socket.c b/net/socket.c > index 32e78de..5c9f2eb 100644 > --- a/net/socket.c > +++ b/net/socket.c > @@ -695,12 +695,18 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk, > } > } > > + /* Received packets may have both SW and HW timestamps in one control > + * message. Transmitted packets may have only one timestamp in the > + * control message, but there may be two separate messages in the error > + * queue if the SOF_TIMESTAMPING_OPT_MULTIMSG option is enabled. > + */ Unnecessary comment, and inexact given SCM_TSTAMP_SCHED and others. > memset(&tss, 0, sizeof(tss)); > if ((sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE) && > ktime_to_timespec_cond(skb->tstamp, tss.ts + 0)) > empty = 0; > if (shhwtstamps && > (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) && > + (empty || !skb_is_err_queue(skb)) && > ktime_to_timespec_cond(shhwtstamps->hwtstamp, tss.ts + 2)) { > if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_PKTINFO && > shhwtstamps->if_index) { > -- > 2.9.3 >
On Thu, Apr 13, 2017 at 10:30:32AM -0400, Willem de Bruijn wrote: > On Wed, Apr 12, 2017 at 10:17 AM, Miroslav Lichvar <mlichvar@redhat.com> wrote: > > +SOF_TIMESTAMPING_OPT_MULTIMSG: > > + > > + Allow outgoing packets to be looped multiple times to the socket's > > + error queue in order to receive both software and hardware transmit > > + timestamps. > > + > > It is already possible to receive multiple copies of the same message. > Timestamps of type SCM_TSTAMP_SCHED will be passed for every > device, virtual or physical, such as bonding. With TCP retransmits, > multiple SCM_TSTAMP_SND can be observed. Oh, I see. I was struggling to find a good name for this option. > The name for this option is therefore not very descriptive. Perhaps > SOF_TIMESTAMPING_OPT_BOTH_SW_HW. Simultaneous SW/HW timestamping was already possible for incoming packets. Maybe _OPT_TX_SWHW would be better?
> -----Original Message----- > From: Miroslav Lichvar [mailto:mlichvar@redhat.com] > Sent: Thursday, April 13, 2017 8:00 AM > > Oh, I see. I was struggling to find a good name for this option. > > > The name for this option is therefore not very descriptive. Perhaps > > SOF_TIMESTAMPING_OPT_BOTH_SW_HW. > > Simultaneous SW/HW timestamping was already possible for incoming > packets. Maybe _OPT_TX_SWHW would be better? > This sounds more accurate to me. Thanks, Jake > -- > Miroslav Lichvar
On Thu, Apr 13, 2017 at 11:24 AM, Keller, Jacob E <jacob.e.keller@intel.com> wrote: > > >> -----Original Message----- >> From: Miroslav Lichvar [mailto:mlichvar@redhat.com] >> Sent: Thursday, April 13, 2017 8:00 AM >> >> Oh, I see. I was struggling to find a good name for this option. >> >> > The name for this option is therefore not very descriptive. Perhaps >> > SOF_TIMESTAMPING_OPT_BOTH_SW_HW. >> >> Simultaneous SW/HW timestamping was already possible for incoming >> packets. Maybe _OPT_TX_SWHW would be better? >> > > This sounds more accurate to me. Agreed.
diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt index ed04aaa..8f30385 100644 --- a/Documentation/networking/timestamping.txt +++ b/Documentation/networking/timestamping.txt @@ -201,6 +201,12 @@ SOF_TIMESTAMPING_OPT_PKTINFO: this information, it will be attached in struct scm_ts_pktinfo as a separate control message of type SCM_TIMESTAMPING_PKTINFO. +SOF_TIMESTAMPING_OPT_MULTIMSG: + + Allow outgoing packets to be looped multiple times to the socket's + error queue in order to receive both software and hardware transmit + timestamps. + New applications are encouraged to pass SOF_TIMESTAMPING_OPT_ID to disambiguate timestamps and SOF_TIMESTAMPING_OPT_TSONLY to operate regardless of the setting of sysctl net.core.tstamp_allow_data. @@ -320,8 +326,10 @@ struct scm_timestamping { }; The structure can return up to three timestamps. This is a legacy -feature. Only one field is non-zero at any time. Most timestamps -are passed in ts[0]. Hardware timestamps are passed in ts[2]. +feature. Most timestamps are passed in ts[0]. Hardware timestamps +are passed in ts[2]. Incoming packets may have timestamps in both +ts[0] and ts[2], but for outgoing packets only one field is non-zero +at any time. ts[1] used to hold hardware timestamps converted to system time. Instead, expose the hardware clock device on the NIC directly as diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index e91685a..0387c4b 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3302,8 +3302,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb, static inline void sw_tx_timestamp(struct sk_buff *skb) { - if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP && - !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)) + if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP) skb_tstamp_tx(skb, NULL); } diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h index 8397ecd..887e3ff 100644 --- a/include/uapi/linux/net_tstamp.h +++ b/include/uapi/linux/net_tstamp.h @@ -27,8 +27,9 @@ enum { SOF_TIMESTAMPING_OPT_TSONLY = (1<<11), SOF_TIMESTAMPING_OPT_STATS = (1<<12), SOF_TIMESTAMPING_OPT_PKTINFO = (1<<13), + SOF_TIMESTAMPING_OPT_MULTIMSG = (1<<14), - SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_PKTINFO, + SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_MULTIMSG, SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) | SOF_TIMESTAMPING_LAST }; diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 7ca251f..d3df8ff 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3863,6 +3863,10 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb, if (!sk) return; + if (!hwtstamps && !(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_MULTIMSG) && + skb_shinfo(orig_skb)->tx_flags & SKBTX_IN_PROGRESS) + return; + tsonly = sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TSONLY; if (!skb_may_tx_timestamp(sk, tsonly)) return; diff --git a/net/socket.c b/net/socket.c index 32e78de..5c9f2eb 100644 --- a/net/socket.c +++ b/net/socket.c @@ -695,12 +695,18 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk, } } + /* Received packets may have both SW and HW timestamps in one control + * message. Transmitted packets may have only one timestamp in the + * control message, but there may be two separate messages in the error + * queue if the SOF_TIMESTAMPING_OPT_MULTIMSG option is enabled. + */ memset(&tss, 0, sizeof(tss)); if ((sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE) && ktime_to_timespec_cond(skb->tstamp, tss.ts + 0)) empty = 0; if (shhwtstamps && (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) && + (empty || !skb_is_err_queue(skb)) && ktime_to_timespec_cond(shhwtstamps->hwtstamp, tss.ts + 2)) { if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_PKTINFO && shhwtstamps->if_index) {
Add SOF_TIMESTAMPING_OPT_MULTIMSG option to allow looping the outgoing packet to the socket's error queue with a software timestamp even when a hardware transmit timestamp is expected to be provided by the driver. Applications using this option will receive two separate messages from the error queue, one with a software timestamp and the other with a hardware timestamp. As the hardware timestamp is saved to the shared skb info, which may happen before the first message with software timestamp is received by the application, the hardware timestamp is copied to the SCM_TIMESTAMPING control message only when the skb has no software timestamp. CC: Richard Cochran <richardcochran@gmail.com> CC: Willem de Bruijn <willemb@google.com> Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com> --- Documentation/networking/timestamping.txt | 12 ++++++++++-- include/linux/skbuff.h | 3 +-- include/uapi/linux/net_tstamp.h | 3 ++- net/core/skbuff.c | 4 ++++ net/socket.c | 6 ++++++ 5 files changed, 23 insertions(+), 5 deletions(-)