- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Fix typo in comment.

MFC after: 3 days

Add TCP scalability testing wrapper scripts for tcpp.

Sponsored by: Juniper Networks
MFC after: 1 week

Revised tuning advice for tcpp benchmarking: do it in loader.conf, and
tweak more TCP/stack parameters.

Sponsored by: Juniper Networks
MFC after: 1 week

Rework tcpp output so that it generates a comma-delimited list of values,
optionally with a header if "-h" is passed. Toast CPU time measurement
in the server for now. Remove -C and -T, since we now always report
both connections/sec and Gb/sec.

MFC after: 1 week
Sponsored by: Juniper Networks

Although we currently don't compile in CPU-pinning support by default,
add a -P to enable it if it were.

MFC after: 1 week
Sponsored by: Juniper Networks

Merge @176820, @176822, @177156 to tcpp from P4 to HEAD:

Improve accuracy of connection data transfer math.

Disable Nagle's algorithm to avoid delaying transfers of data --
will want to refine this to combine payload with header transfer,
however.

Now that we're running w/o Nagle, try to send the initial data
burst with the header in a single TCP segment.

Prefer %zu to %ju for size_t.

MFC after: 1 week
Sponsored by: Juniper, Inc.

Always assign WARNS using ?=

- fix some nearby style bugs
- include Makefile.inc where it makes sense and reduces duplication

Approved by: ed (co-mentor)

Add tcpp -- TCP parallelism microbenchmark.

This tool creates large numbers of TCP connections, each of which will
transmit a fixed amount of data, between client and server hosts. tcpp can
use multiple workers (typically up to the number of hardware cores), and can
use multiple source IPs in order to use an expanded port/IP 4-tuple space to
avoid problems from reusing 4-tuples too quickly. Aggregate bandwidth use
will be reported after a client run.

While by no means a perfect tool, it has proven quite useful in generating
and optimizing TCP stack lock contention by easily generating high-intensity
workloads. It also proves surprisingly good at finding device driver bugs.