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Clarify calculations a little for #5

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Ordering of ramping cases was a bit over the shop, so cleaned up.
Comment about slope definitions was out of sync.  Comment about
$demand range clarified.  Some mathematical terms bracketed to be
less ambiguous.  Fixes #5.
This commit is contained in:
Tim Connors 2024-11-15 14:05:18 +11:00
parent be27b2e538
commit e29a05f4ab
1 changed files with 13 additions and 10 deletions
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23
fan-speed-control.pl
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@ -121,40 +121,43 @@ sub set_fans_servo {
average(@cputemps), average(@coretemps), average(@hddtemps)),
average(@hddtemps));
if (!defined $weighted_temp or $weighted_temp == 0) {
if ((!defined $weighted_temp) or ($weighted_temp == 0)) {
print "Error reading all temperatures! Fallback to idrac control\n";
set_fans_default();
return;
}
print "weighted_temp = $weighted_temp ; ambient_temp $ambient_temp\n" if $print_stats;
if (!defined $current_mode or $current_mode ne "set") {
$current_mode="set";
if ((!defined $current_mode) or ($current_mode ne "set")) {
print "--> disable dynamic fan control\n";
system("ipmitool raw 0x30 0x30 0x01 0x00") == 0 or return 0;
# if this fails, want to return telling caller not to think weve
# made a change
$current_mode="set";
}
# FIXME: probably want to take into account ambient temperature - if
# the difference between weighted_temp and ambient_temp is small
# because ambient_temp is large, then less need to run the fans
# because there's still low power demands
my $demand = 0; # want demand to be a reading from 0-100% of
# $static_speed_low - $static_speed_high
my $demand = 0; # sort of starts off with a range roughly 0-255,
# which we multiply later to be ranged roughly
# between 0-100% of
# ($static_speed_low - $static_speed_high)
if ($weighted_temp > $base_temp and
$weighted_temp < $desired_temp1) {
# slope m = (y2-y1)/(x2-x1)
# y - y1 = (x-x1)(y2-y1)/(x2-x1)
# y1 = 0 ; x1 = base_temp ; y2 = demand1 ; x2 = desired_temp1
# x = weighted_temp
$demand = 0 + ($weighted_temp - $base_temp) * ($demand1 - 0)/($desired_temp1 - $base_temp);
} elsif ($weighted_temp >= $desired_temp2) {
# y1 = demand1 ; x1 = desired_temp1 ; y2 = demand2 ; x2 = desired_temp2
$demand = $demand2 + ($weighted_temp - $desired_temp2) * ($demand3 - $demand2)/($desired_temp3 - $desired_temp2);
} elsif ($weighted_temp >= $desired_temp1) {
$demand = 0 + ($weighted_temp - $base_temp ) * ($demand1 - 0 )/($desired_temp1 - $base_temp );
} elsif (($weighted_temp >= $desired_temp1) or ($weighted_temp < $desired_temp2)) {
# y1 = demand1 ; x1 = desired_temp1 ; y2 = demand2 ; x2 = desired_temp2
$demand = $demand1 + ($weighted_temp - $desired_temp1) * ($demand2 - $demand1)/($desired_temp2 - $desired_temp1);
} elsif ($weighted_temp >= $desired_temp2) {
# y1 = demand2 ; x1 = desired_temp2 ; y2 = demand3 ; x2 = desired_temp3
# demand will increase above $demand3 for temps above $desired_temp3, linearly, until we cap it below
$demand = $demand2 + ($weighted_temp - $desired_temp2) * ($demand3 - $demand2)/($desired_temp3 - $desired_temp2);
}
printf "demand(%0.2f)", $demand if $print_stats;
$demand = int($static_speed_low + $demand/100*($static_speed_high-$static_speed_low));