@@ -140,6 +140,15 @@ SOF_TIMESTAMPING_TX_ACK:
cumulative acknowledgment. The mechanism ignores SACK and FACK.
This flag can be enabled via both socket options and control messages.
+SOF_TIMESTAMPING_TX_COMPLETION:
+ Request tx timestamps on packet tx completion. The completion
+ timestamp is generated by the kernel when it receives packet a
+ completion report from the hardware. Hardware may report multiple
+ packets at once, and completion timestamps reflect the timing of the
+ report and not actual tx time. The completion timestamps are
+ currently implemented only for: Bluetooth L2CAP and ISO. This
+ flag can be enabled via both socket options and control messages.
+
1.3.2 Timestamp Reporting
^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -489,10 +489,14 @@ enum {
/* generate software time stamp when entering packet scheduling */
SKBTX_SCHED_TSTAMP = 1 << 6,
+
+ /* generate software time stamp on packet tx completion */
+ SKBTX_COMPLETION_TSTAMP = 1 << 7,
};
#define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | \
- SKBTX_SCHED_TSTAMP)
+ SKBTX_SCHED_TSTAMP | \
+ SKBTX_COMPLETION_TSTAMP)
#define SKBTX_ANY_TSTAMP (SKBTX_HW_TSTAMP | \
SKBTX_HW_TSTAMP_USE_CYCLES | \
SKBTX_ANY_SW_TSTAMP)
@@ -73,6 +73,7 @@ enum {
SCM_TSTAMP_SND, /* driver passed skb to NIC, or HW */
SCM_TSTAMP_SCHED, /* data entered the packet scheduler */
SCM_TSTAMP_ACK, /* data acknowledged by peer */
+ SCM_TSTAMP_COMPLETION, /* packet tx completion */
};
#endif /* _UAPI_LINUX_ERRQUEUE_H */
@@ -44,8 +44,9 @@ enum {
SOF_TIMESTAMPING_BIND_PHC = (1 << 15),
SOF_TIMESTAMPING_OPT_ID_TCP = (1 << 16),
SOF_TIMESTAMPING_OPT_RX_FILTER = (1 << 17),
+ SOF_TIMESTAMPING_TX_COMPLETION = (1 << 18),
- SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_RX_FILTER,
+ SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_TX_COMPLETION,
SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) |
SOF_TIMESTAMPING_LAST
};
@@ -58,7 +59,8 @@ enum {
#define SOF_TIMESTAMPING_TX_RECORD_MASK (SOF_TIMESTAMPING_TX_HARDWARE | \
SOF_TIMESTAMPING_TX_SOFTWARE | \
SOF_TIMESTAMPING_TX_SCHED | \
- SOF_TIMESTAMPING_TX_ACK)
+ SOF_TIMESTAMPING_TX_ACK | \
+ SOF_TIMESTAMPING_TX_COMPLETION)
/**
* struct so_timestamping - SO_TIMESTAMPING parameter
@@ -431,6 +431,7 @@ const char sof_timestamping_names[][ETH_GSTRING_LEN] = {
[const_ilog2(SOF_TIMESTAMPING_BIND_PHC)] = "bind-phc",
[const_ilog2(SOF_TIMESTAMPING_OPT_ID_TCP)] = "option-id-tcp",
[const_ilog2(SOF_TIMESTAMPING_OPT_RX_FILTER)] = "option-rx-filter",
+ [const_ilog2(SOF_TIMESTAMPING_TX_COMPLETION)] = "completion-transmit",
};
static_assert(ARRAY_SIZE(sof_timestamping_names) == __SOF_TIMESTAMPING_CNT);
@@ -693,6 +693,9 @@ void __sock_tx_timestamp(__u32 tsflags, __u8 *tx_flags)
if (tsflags & SOF_TIMESTAMPING_TX_SCHED)
flags |= SKBTX_SCHED_TSTAMP;
+ if (tsflags & SOF_TIMESTAMPING_TX_COMPLETION)
+ flags |= SKBTX_COMPLETION_TSTAMP;
+
*tx_flags = flags;
}
EXPORT_SYMBOL(__sock_tx_timestamp);
Add SOF_TIMESTAMPING_TX_COMPLETION, for requesting a software timestamp when hardware reports a packet completed. Completion tstamp is useful for Bluetooth, where hardware tx timestamps cannot be obtained except for ISO packets, and the hardware has a queue where packets may wait. In this case the software SND timestamp only reflects the kernel-side part of the total latency (usually small) and queue length (usually 0 unless HW buffers congested), whereas the completion report time is more informative of the true latency. It may also be useful in other cases where HW TX timestamps cannot be obtained and user wants to estimate an upper bound to when the TX probably happened. Signed-off-by: Pauli Virtanen <pav@iki.fi> --- Documentation/networking/timestamping.rst | 9 +++++++++ include/linux/skbuff.h | 6 +++++- include/uapi/linux/errqueue.h | 1 + include/uapi/linux/net_tstamp.h | 6 ++++-- net/ethtool/common.c | 1 + net/socket.c | 3 +++ 6 files changed, 23 insertions(+), 3 deletions(-)