The resizing could be a downsizing so some data would be lost and we
could attempt to read past the end of the new memory allocation.
MFC after: 2 weeks
Sponsored by: Panzura
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.
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
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
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
gets rid of the duplicated code in compute_stats().
Add a new DSM_SKIP statistic type for devstat_compute_statistics() that
causes the subsequent variable argument to be skipped.
Thanks to Sergey Osokin for coding up my idea/code fragment.
Submitted by: "Sergey A. Osokin" <osa@freebsd.org.ru>
1.) prefix all functions in the library with devstat_ (compatability
functions are available for all functions that were chaned in an
incompatible way, but are deprecated).
2.) Add a pointer to a kvm_t as the first argument to functions that
used to get their information via sysctl; they behave the same
as before when NULL is passed as this argument, otherwise, the
information is obtained via libkvm using the supplied handle.
3.) Add a new function, devstat_compute_statistics(), that is intended
to replace the old compute_stats() function. It offers more
statistics data, and has a more flexible interface.
libdevstat does now require libkvm; a library depedency is added, so
that libkvm only needs to be explicitely specified for statically linked
programs.
The library major version number is bumped.
Submitted by: Sergey A. Osokin <osa@freebsd.org.ru>, ken (3)
Reviewed by: ken
generation was causing unaligned access faults on the Alpha.
I have incremented the devstat version number, since this is an interface
change. You'll need to recompile libdevstat, systat, iostat, vmstat and
rpc.rstatd along with your kernel.
Partially Submitted by: Andrew Gallatin <gallatin@cs.duke.edu>
