linux/arch/s390
Francis Yan 1c885808e4 tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING
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 <francisyyan@gmail.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-30 10:04:25 -05:00
..
appldata
boot s390: enable UBSAN 2016-09-20 14:26:23 +02:00
configs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2016-10-04 14:05:52 -07:00
crypto
hypfs s390/hypfs: Use get_free_page() instead of kmalloc to ensure page alignment 2016-10-28 10:08:58 +02:00
include tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING 2016-11-30 10:04:25 -05:00
kernel mm: kmemleak: scan .data.ro_after_init 2016-11-11 08:12:37 -08:00
kvm KVM: s390: Fix STHYI buffer alignment for diag224 2016-10-26 13:46:44 +02:00
lib Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-10-14 14:26:58 -07:00
mm Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2016-10-27 14:16:30 -07:00
net
numa
oprofile s390/dumpstack: restore reliable indicator for call traces 2016-10-17 14:44:30 +02:00
pci s390: pci: don't print uninitialized data for debugging 2016-11-11 08:45:08 -08:00
tools
defconfig
Kbuild
Kconfig atomic64: no need for CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE 2016-10-07 18:46:30 -07:00
Kconfig.debug
Makefile