`process.uptime()` interface will return the amount of time the
current process has been running. To achieve this it was caching the
`uv_uptime` value at program start, and then on the call to
`process.uptime()` returning the delta between the two values.

`uv_uptime` is defined as the number of seconds the operating system
has been up since last boot. On sunos this interface uses `kstat`s
which can be a significantly expensive operation as it requires
exclusive access, but because of the design of `process.uptime()` node
*had* to always call this on start. As a result if you had many node
processes all starting at the same time you would suffer lock
contention as they all tried to read kstats.

Instead of using `uv_uptime` to achieve this, the libuv loop already
has a concept of current loop time in the form of `uv_now()` which is
in fact monotonically increasing, and already stored directly on the
loop. By using this value at start every platform performs at least
one fewer syscall during initialization.

Since the interface to `uv_uptime` is defined as seconds, in the call
to `process.uptime()` we now `uv_update_time` get our delta, divide by
1000 to get seconds, and then convert to an `Integer`. In 0.12 we can
move back to `Number::New` instead and not lose precision.

Caveat: For some platforms `uv_uptime` reports time monotonically
increasing regardless of system hibernation, `uv_now` interface is
also monotonically increasing but may not reflect time spent in
hibernation.

Signed-off-by: Fedor Indutny <fedor@indutny.com>

Fix possible deadlock, when handles are sent in both direction
simultaneously. In such rare cases, both sides may queue their
`NODE_HANDLE_ACK` replies and wait for them.

fix #7465

See https://code.google.com/p/chromium/issues/detail?id=25916

Parse URLs with backslashes the same as web browsers, by replacing all
backslashes with forward slashes, except those that occur after the
first # character.

* isaacs, Robert Kowalski, Benjamin Coe: Test Improvements
* isaacs doc: Add canonical url
* isaacs view: handle unpublished packages properly
* Raynos (Jake Verbaten) do not log if silent
* Julian Gruber fix no such property error
* isaacs npmconf@0.1.14
* Thorsten Lorenz adding save-prefix configuration option
* isaacs npm-registry-client@0.4.7
* isaacs cache: treat missing versions as a 404
* isaacs cache: Save shasum, write resolved/etc data to cache
* isaacs cache: Always fetch root doc
* isaacs cache: don't repack unnecessarily from tmp
* Andrey Kislyuk Don't crash if shrinkwrap-dependencies were not passed in pkginfo
* Robert Kowalski fix link in faq
* Jean Lauliac Add a peerDependencies section in package.json doc
* isaacs read-installed@2.0.2

This reverts commit 896e193.

Proper handling of TXT records requires API change, we can't afford it
in v0.10.

See #7371 for details.

Signed-off-by: Fedor Indutny <fedor@indutny.com>

Signed-off-by: Fedor Indutny <fedor@indutny.com>

Date.now() indirectly calls gettimeofday() on Linux and that's a system
call that is extremely expensive on virtualized systems when the host
operating system has to emulate access to the hardware clock.

Case in point: output from `perf record -c 10000 -e cycles:u -g -i`
for a benchmark/http_simple bytes/8 benchmark with a light load of
50 concurrent clients:

    53.69%     node  node                 [.] v8::internal::OS::TimeCurrentMillis()
               |
               --- v8::internal::OS::TimeCurrentMillis()
                  |
                  |--99.77%-- v8::internal::Runtime_DateCurrentTime(v8::internal::Arguments, v8::internal::Isolate*)
                  |          0x23587880618e

That's right - over half of user time spent inside the V8 function that
calls gettimeofday().

Notably, nearly all system time gets attributed to acpi_pm_read(), the
kernel function that reads the ACPI power management timer:

    32.49%     node  [kernel.kallsyms]    [k] acpi_pm_read
               |
               --- acpi_pm_read
                  |
                  |--98.40%-- __getnstimeofday
                  |          getnstimeofday
                  |          |
                  |          |--71.61%-- do_gettimeofday
                  |          |          sys_gettimeofday
                  |          |          system_call_fastpath
                  |          |          0x7fffbbaf6dbc
                  |          |          |
                  |          |          |--98.72%-- v8::internal::OS::TimeCurrentMillis()

The cost of the gettimeofday() system call is normally measured in
nanoseconds but we were seeing 100 us averages and spikes >= 1000 us.
The numbers were so bad, my initial hunch was that the node process was
continuously getting rescheduled inside the system call...

v8::internal::OS::TimeCurrentMillis()'s most frequent caller is
v8::internal::Runtime_DateCurrentTime(), the V8 run-time function
that's behind Date.now().  The timeout handling logic in lib/http.js
and lib/net.js calls into lib/timers.js and that module will happily
call Date.now() hundreds or even thousands of times per second.
If you saw exports._unrefActive() show up in --prof output a lot,
now you know why.

That's why this commit makes V8 switch over to clock_gettime() on Linux.
In particular, it checks if CLOCK_REALTIME_COARSE is available and has
a resolution <= 1 ms because in that case the clock_gettime() call can
be fully serviced from the vDSO.

It speeds up the aforementioned benchmark by about 100% on the affected
systems and should go a long way toward addressing the latency issues
that StrongLoop customers have been reporting.

This patch will be upstreamed as a CR against V8 3.26.  I'm sending it
as a pull request for v0.10 first because that's what our users are
running and because the delta between 3.26 and 3.14 is too big to
reasonably back-port the patch.  I'll open a pull request for the
master branch once the CR lands upstream.

Signed-off-by: Trevor Norris <trev.norris@gmail.com>
Signed-off-by: Fedor Indutny <fedor@indutny.com>

Conflicts:
	lib/util.js
	test/simple/test-util-format.js

This is a backport to fix #7253

Signed-off-by: Fedor Indutny <fedor@indutny.com>

Commit f9ced08 switches V8 on Linux over from gettimeofday() to
clock_getres() and clock_gettime().  As of glibc 2.17, those functions
live in libc.  For older versions, we need to pull them in from librt.

Fixes the following link-time error;

    Release/obj.target/deps/v8/tools/gyp/libv8_base.a(platform-posix.o):
    In function `v8::internal::OS::Ticks()':
    platform-posix.cc:(.text+0x93c):
    undefined reference to `clock_gettime'
    platform-posix.cc:(.text+0x989):
    undefined reference to `clock_getres'

Fixes #7514.

Signed-off-by: Fedor Indutny <fedor@indutny.com>

Signed-off-by: Fedor Indutny <fedor@indutny.com>

* Check SHA before using files from cache
* adduser: allow change of the saved password
* Make `npm install` respect `config.unicode`
* Fix lifecycle to pass `Infinity` for config env value
* Don't return 0 exit code on invalid command
* cache: Handle 404s and other HTTP errors as errors
* bump tap dep, make tests stderr a bit quieter
* Resolve ~ in path configs to env.HOME
* Include npm version in default user-agent conf
* npm init: Use ISC as default license, use save-prefix for deps
* Many test and doc fixes

Reverted 9520ade

Conflicts:
	deps/cares/src/ares_parse_txt_reply.c
	deps/uv/.mailmap
	deps/uv/AUTHORS
	deps/uv/ChangeLog
	deps/uv/include/uv.h
	deps/uv/src/unix/error.c
	deps/uv/src/unix/process.c
	deps/uv/src/version.c
	deps/uv/src/win/pipe.c
	deps/uv/src/win/signal.c
	deps/uv/src/win/util.c
	deps/uv/test/test-spawn.c
	deps/uv/vcbuild.bat
	deps/v8/src/platform-posix.cc
	deps/v8/tools/gyp/v8.gyp
	lib/util.js
	src/node.cc
	test/simple/test-util-format.js
	test/simple/test-util.js