lib: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
pr

lib: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

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Remove unused variable and silence clang warnings.

Differential Revision: D2681
Reviewed by: rodrigc

Remove an obsolete comment in devstat(3) about the accuracy of the
milliseconds per transaction (DSM_MS_PER_TRANSACTION) calculation.

The comment was accurate many years ago when the kernel didn't
r

Remove an obsolete comment in devstat(3) about the accuracy of the
milliseconds per transaction (DSM_MS_PER_TRANSACTION) calculation.

The comment was accurate many years ago when the kernel didn't
record I/O times on a per-I/O basis, but now that we do collect
that information in most areas, it isn't correct.

The milliseconds per transaction values are correct, assuming the
I/O duration has been recorded.

Sponsored by: Spectra Logic
MFC after: 3 days

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Fix a typo.

For vmcore, calculate time relative to device creation upon time_uptime.
Previously it used a clock from live kernel.

MFC after: 2 weeks

New devstat metrics for devstat_compute_statistics():

DSM_TOTAL_DURATION
DSM_TOTAL_DURATION_READ
DSM_TOTAL_DURATION_WRITE
DSM_TOTAL_DURATION_FREE
DSM_TOTAL_DURATION_OTHER
DSM_TOTAL_BUSY_

New devstat metrics for devstat_compute_statistics():

DSM_TOTAL_DURATION
DSM_TOTAL_DURATION_READ
DSM_TOTAL_DURATION_WRITE
DSM_TOTAL_DURATION_FREE
DSM_TOTAL_DURATION_OTHER
DSM_TOTAL_BUSY_TIME

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Handle memory allocation failures in devstat_getdevs(), devstat_selectdevs(),
and devstat_buildmatch().

PR: bin/83359
Reviewed by: ken

Do not increment num_args if strsep(3) returned an empty field.
That fixes devstat_buildmatch(3) crashes with certain strings.

Reported by: arundel
MFC after: 2 weeks

Remove an unused variable.

Reviewed by: ken

Use __func__ throughout devstat.c instead of defining a func_name
variable in each function.

Make this compile with GCC4 by fixing a signedness issue.

Reviewed by: md5(1)

Remove the use of cast as lvalue. GCC 3.4 isses a deprecation warning
for this now.

Include <nlist.h> for nlist-related declarations instead of depending on
namespace pollution in <kvm.h>.

It is not an error to have no devices.

Add prototype for compute_stats() so that libdevstat is WARNS=4 clean.

Spotted by: kris

If rounding results in -epsilon device busy %, set it to zero.

typo

Further unbreak devstat: sort the index array in correct order too.

Add more devstat calculations, mostly filling in holes, but also adding
a couple of reqests: DSM_BUSY_PCT and DSM_QUEUE_LENGTH.

I have no further plans for mutilating this API at this point in
time

Add more devstat calculations, mostly filling in holes, but also adding
a couple of reqests: DSM_BUSY_PCT and DSM_QUEUE_LENGTH.

I have no further plans for mutilating this API at this point in
time, and will update the man-page to reflect current reality as
the next thing.

Reviewed by: ken

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And I managed to make a regression here too.

I have too many source trees :-(

Run a revision of the devstat interface:

Kernel:

Change statistics to use the *uptime() timescale (ie: relative to
boottime) rather than the UTC aligned timescale. This makes the
device statistics

Run a revision of the devstat interface:

Kernel:

Change statistics to use the *uptime() timescale (ie: relative to
boottime) rather than the UTC aligned timescale. This makes the
device statistics code oblivious to clock steps.

Change timestamps to bintime format, they are cheaper.

Remove the "busy_count", and replace it with two counter fields:
"start_count" and "end_count", which are updated in the down and
up paths respectively. This removes the locking constraint on
devstat.

Add a timestamp argument to devstat_start_transaction(), this will
normally be a timestamp set by the *_bio() function in bp->bio_t0.
Use this field to calculate duration of I/O operations.

Add two timestamp arguments to devstat_end_transaction(), one is
the current time, a NULL pointer means "take timestamp yourself",
the other is the timestamp of when this transaction started (see
above).

Change calculation of busy_time to operate on "the salami principle":
Only when we are idle, which we can determine by the start+end
counts being identical, do we update the "busy_from" field in the
down path. In the up path we accumulate the timeslice in busy_time
and update busy_from.

Change the byte_* and num_* fields into two arrays: bytes[] and
operations[].

Userland:

Change the misleading "busy_time" name to be called "snap_time" and
make the time long double since that is what most users need anyway,
fill it using clock_gettime(CLOCK_MONOTONIC) to put it on the same
timescale as the kernel fields.

Change devstat_compute_etime() to operate on struct bintime.

Remove the version 2 legacy interface: the change to bintime makes
compatibility far too expensive.

Fix a bug in systat's "vm" page where boot relative busy times would
be bogus.

Bump __FreeBSD_version to 500107

Review & Collaboration by: ken

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Remove include of <sys/dkstat.h>

Premptively include <sys/resource.h> to get the cp_time[CPUSTATES].

Remove 'register' keyword.

Turn on WARNS?= 2 for libdevstat.

Submitted by: "Sergey A. Osokin" <[email protected]>