kernel/linux.git/Documentation/networking/timestamping.txt, branch linux-5.3.y

docs: ptp.txt: convert to ReST and move to driver-api

2019-06-14T20:31:27+00:00

The conversion is trivial: just adjust title markups. In order to avoid conflicts, let's add an :orphan: tag to it, to be removed when this file gets added to the driver-api book. Signed-off-by: Mauro Carvalho Chehab Acked-by: Richard Cochran Signed-off-by: Jonathan Corbet

socket: Update timestamping Documentation

2019-02-03T19:17:31+00:00

With the new y2038 safe timestamping options added, update the documentation to reflect the changes. Signed-off-by: Deepa Dinamani Acked-by: Willem de Bruijn Signed-off-by: David S. Miller

Documentation: timestamping: correct path to net_tstamp.h

2019-01-18T05:39:59+00:00

net_tstamp.h is an UAPI header, so it was moved under include/uapi. Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller

net: Fix minor code bug in timestamping.txt

2017-07-11T20:34:54+00:00

Passing (void*)val instead of &val would make a pointer out of an integer and cause sock_setsockopt to -EFAULT. See tools/testing/selftests/networking/timestamping/timestamping.c for a working example. Cc: David S. Miller Cc: netdev@vger.kernel.org Signed-off-by: Ahmad Fatoum Signed-off-by: David S. Miller

net: allow simultaneous SW and HW transmit timestamping

2017-05-21T17:37:32+00:00

Add SOF_TIMESTAMPING_OPT_TX_SWHW option to allow an outgoing packet to be looped 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 or it is an incoming packet. While changing sw_tx_timestamp(), inline it in skb_tx_timestamp() as there are no other users. CC: Richard Cochran CC: Willem de Bruijn Signed-off-by: Miroslav Lichvar Acked-by: Willem de Bruijn Signed-off-by: David S. Miller

net: fix documentation of struct scm_timestamping

2017-05-21T17:37:32+00:00

The scm_timestamping struct may return multiple non-zero fields, e.g. when both software and hardware RX timestamping is enabled, or when the SO_TIMESTAMP(NS) option is combined with SCM_TIMESTAMPING and a false software timestamp is generated in the recvmsg() call in order to always return a SCM_TIMESTAMP(NS) message. CC: Richard Cochran CC: Willem de Bruijn Signed-off-by: Miroslav Lichvar Acked-by: Willem de Bruijn Signed-off-by: David S. Miller

net: add new control message for incoming HW-timestamped packets

2017-05-21T17:37:32+00:00

Add SOF_TIMESTAMPING_OPT_PKTINFO option to request a new control message for incoming packets with hardware timestamps. It contains the index of the real interface which received the packet and the length of the packet at layer 2. The index is useful with bonding, bridges and other interfaces, where IP_PKTINFO doesn't allow applications to determine which PHC made the timestamp. With the L2 length (and link speed) it is possible to transpose preamble timestamps to trailer timestamps, which are used in the NTP protocol. While this information could be provided by two new socket options independently from timestamping, it doesn't look like they would be very useful. With this option any performance impact is limited to hardware timestamping. Use dev_get_by_napi_id() to get the device and its index. On kernels with disabled CONFIG_NET_RX_BUSY_POLL or drivers not using NAPI, a zero index will be returned in the control message. CC: Richard Cochran Acked-by: Willem de Bruijn Signed-off-by: Miroslav Lichvar Signed-off-by: David S. Miller

tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING

2016-11-30T15:04:25+00:00

This patch exports the sender chronograph stats via the socket SO_TIMESTAMPING channel. Currently we can instrument how long a particular application unit of data was queued in TCP by tracking SOF_TIMESTAMPING_TX_SOFTWARE and SOF_TIMESTAMPING_TX_SCHED. Having these sender chronograph stats exported simultaneously along with these timestamps allow further breaking down the various sender limitation. For example, a video server can tell if a particular chunk of video on a connection takes a long time to deliver because TCP was experiencing small receive window. It is not possible to tell before this patch without packet traces. To prepare these stats, the user needs to set SOF_TIMESTAMPING_OPT_STATS and SOF_TIMESTAMPING_OPT_TSONLY flags while requesting other SOF_TIMESTAMPING TX timestamps. When the timestamps are available in the error queue, the stats are returned in a separate control message of type SCM_TIMESTAMPING_OPT_STATS, in a list of TLVs (struct nlattr) of types: TCP_NLA_BUSY_TIME, TCP_NLA_RWND_LIMITED, TCP_NLA_SNDBUF_LIMITED. Unit is microsecond. Signed-off-by: Francis Yan Signed-off-by: Yuchung Cheng Signed-off-by: Soheil Hassas Yeganeh Acked-by: Neal Cardwell Signed-off-by: David S. Miller

sock: document timestamping via cmsg in Documentation

2016-04-04T19:50:30+00:00

Update docs and add code snippet for using cmsg for timestamping. Signed-off-by: Soheil Hassas Yeganeh Acked-by: Willem de Bruijn Signed-off-by: David S. Miller

clarify implementation of ethtool's get_ts_info op

2015-07-18T02:59:04+00:00

This patch adds some clarification about the intended way to implement both SIOCSHWTSTAMP and ethtool's get_ts_info. The HWTSTAMP API has several Rx filters which are very specific, as well as more general filters. The specific filters really only exist to support some broken hardware which can't fully implement the generic filters. This patch adds clarification that it is okay to support the specific filters in SIOCSHWTSTAMP by upscaling them to the generic filters. In addition, update the header for ethtool_ts_info to specify that drivers ought to only report the filters they support without upscaling in this manner. Signed-off-by: Jacob Keller Acked-by: Richard Cochran Tested-by: Phil Schmitt Reviewed-by: Aaron Brown Signed-off-by: Jeff Kirsher