[PATCH ha-manager 14/16] lrm: read service config once per work iteration

[Daniel Kral <d.kral@proxmox.com>]

Make update_lrm_status() read and parse the HA resources config once per
work() iteration.

This significantly reduces the time spent reading and parsing the HA
resource config every time run_workers() is called and every time a LRM
worker's result is collected with handle_service_exitcode().

This does not change the current behavior as the HA resource config and
vmlist, which are used for the return value of the read_service_config()
in the PVE2 environment, are only updated after every cfs_update().
However, cfs_update() is only called before each work() iteration in
PVE::HA::LRM::do_one_iteration() and in PVE::HA::Env::PVE2::after_fork()
and handle_service_exit_code() is only called from
resource_command_finished(), which in turn is only called from the main
thread and not the worker threads (i.e., after_fork() is not called).

A test startup of 768 HA resources on a single node at the same time
showed ~1,250% less calls to checked_resources_config() (from 10,333 to
82 calls) and ~14,320% less calls to parse_sid() (from 15,639,537 to
109,198 calls).

Additionally, this reduces the inclusive average execution time per call
for several subroutines where the HA resource config was read within:

+---------------------------+---------------+--------------+
|        Subroutine         | Before Change | After Change |
+---------------------------+---------------+--------------+
| check_active_workers      | 327ms         | 11.6ms       |
| resource_command_finished | 22.7ms        | 2.81ms       |
| handle_service_exitcode   | 21.1ms        | 10µs         |
+---------------------------+---------------+--------------+

The profiling was done on a physical host with Devel::NYTProf 6.14 [0].

[0] https://metacpan.org/pod/Devel::NYTProf

Signed-off-by: Daniel Kral <d.kral@proxmox.com>
---
 src/PVE/HA/LRM.pm | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/PVE/HA/LRM.pm b/src/PVE/HA/LRM.pm
index 1a093e8e..5f77580c 100644
--- a/src/PVE/HA/LRM.pm
+++ b/src/PVE/HA/LRM.pm
@@ -41,6 +41,9 @@ sub new {
         mode => 'active',
         cluster_state_update => 0,
         active_idle_rounds => 0,
+        # service_config in current work() iteration
+        # does contain all HA resources, users must filter for the assigned node
+        service_config => {},
         # service_status from manager_status in current work() iteration
         # does contain all HA resources, users must filter for the assigned node
         service_status => {},
@@ -213,10 +216,11 @@ sub flush_lrm_status {
 =head3 $self->update_lrm_status()
 
 Updates the internal LRM status properties to reflect the state given by the
-C<L<manager_status|PVE::HA::Env::read_manager_status()>>.
+C<L<manager_status|PVE::HA::Env::read_manager_status()>> and
+C<L<checked service_config|PVE::HA::Env::read_service_config()>>.
 
 The internal LRM status properties that are updated are C<node_status>,
-C<service_status>, and C<shutdown_request>.
+C<service_config>, C<service_status>, and C<shutdown_request>.
 
 Returns 1 if the update was successful, otherwise returns undef.
 
@@ -232,6 +236,7 @@ sub update_lrm_status {
         $haenv->log('err', "updating service status from manager failed: $err");
         return undef;
     } else {
+        $self->{service_config} = $haenv->read_service_config();
         $self->{service_status} = $ms->{service_status} || {};
         my $nodename = $haenv->nodename();
         $self->{node_status} = $ms->{node_status}->{$nodename} || 'unknown';
@@ -658,13 +663,12 @@ sub work {
 sub run_workers {
     my ($self) = @_;
 
-    my $haenv = $self->{haenv};
+    my ($haenv, $sc) = $self->@{qw(haenv service_config)};
 
     my $starttime = $haenv->get_time();
 
     # number of workers to start, if 0 we exec the command directly without forking
     my $max_workers = $haenv->get_max_workers();
-    my $sc = $haenv->read_service_config();
 
     my $worker = $self->{workers};
     # we only got limited time but want to ensure that every queued worker is scheduled
@@ -909,7 +913,7 @@ sub handle_service_exitcode {
     my $haenv = $self->{haenv};
     my $tries = $self->{restart_tries};
 
-    my $sc = $haenv->read_service_config();
+    my $sc = $self->{service_config};
 
     my $max_restart = 0;
 
-- 
2.47.3