This commit is based on exploratory work by Sohaib Mohamed.
The end goal is two-fold - to support addition of Meters we
build via configuration files for both the PCP platform and
for scripts ( https://github.com/htop-dev/htop/issues/526 )
Here, we focus on generic code and the PCP support. A new
class DynamicMeter is introduced - it uses the special case
'param' field handling that previously was used only by the
CPUMeter, such that every runtime-configured Meter is given
a unique identifier. Unlike with the CPUMeter this is used
internally only. When reading/writing to htoprc instead of
CPU(N) - where N is an integer param (CPU number) - we use
the string name for each meter. For example, if we have a
configuration for a DynamicMeter for some Redis metrics, we
might read and write "Dynamic(redis)". This identifier is
subsequently matched (back) up to the configuration file so
we're able to re-create arbitrary user configurations.
The PCP platform configuration file format is fairly simple.
We expand configs from several directories, including the
users homedir alongside htoprc (below htop/meters/) and also
/etc/pcp/htop/meters. The format will be described via a
new pcp-htop(5) man page, but its basically ini-style and
each Meter has one or more metric expressions associated, as
well as specifications for labels, color and so on via a dot
separated notation for individual metrics within the Meter.
A few initial sample configuration files are provided below
./pcp/meters that give the general idea. The PCP "derived"
metric specification - see pmRegisterDerived(3) - is used
as the syntax for specifying metrics in PCP DynamicMeters.
* Rename internal identifier from TTY_NR to just TTY
* Unify column header on platforms
* Use devname(3) on BSD derivate to show the actual terminal,
simplifies current FreeBSD implementation.
* Use 'unsigned long int' as id type, to fit dev_t on Linux.
Only on Solaris the terminal path is not yet resolved.
Generic data, as CPU and memory usage, are used by Meters.
In paused mode they would stop receiving updates and especially Graph
Meters would stop showing continuous data.
Improves: #214Closes: #253
Reasoning:
- implementation was unsound -- broke down when I added a fairly
basic macro definition expanding to a struct initializer in a *.c
file.
- made it way too easy (e.g. via otherwise totally innocuous git
commands) to end up with timestamps such that it always ran
MakeHeader.py but never used its output, leading to overbuild noise
when running what should be a null 'make'.
- but mostly: it's just an awkward way of dealing with C code.
GCC10 and Clang11 now default to -fno-common.
ld: error: duplicate symbol: jail_errmsg
>>> defined at Platform.c
>>> freebsd/Platform.o:(jail_errmsg)
>>> defined at FreeBSDProcessList.c
>>> freebsd/FreeBSDProcessList.o:(.bss+0x90)
Signed-off-by: Tobias Kortkamp <t@tobik.me>
New meter displays same ARC stats as FreeBSD top(1).
Can be extended to other platforms that support ZFS.
Pulling kstat.zfs.misc.arcstats.c_max as the meter
total, so the meter has a meaningful value to work
up to.
The Text meter displays, first, the maximum
ARC size (Meter.total), then second, the total
ARC used, using the difference between Meter.maxItems
and Meter.curItems to "hide" the used value from the
Bar and Graph drawing functions by using an index
in Meter.values[] that is beyond curItems - 1, but
less than maxItems - 1.
Nathan Scott