From 5a33d25886af8f0996d901fcfc66674a3dc625db Mon Sep 17 00:00:00 2001
From: PA4WDH
Date: Thu, 25 Jul 2024 17:27:28 +0200
Subject: Add commandline parameter to set transition latency

---
 README.html       |  3 +++
 argparse.c        | 12 +++++++++++-
 cputemp2maxfreq.c | 27 +++++++++++++++++++++++++--
 cputemp2maxfreq.h |  1 +
 4 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/README.html b/README.html
index 312f4c6..5ed6157 100644
--- a/README.html
+++ b/README.html
@@ -30,6 +30,9 @@
 </p>
 <p><strong>Scaling options:</strong></p>
 <ul>
+ <li><strong>-d</strong> sets the transition latency (the time it takes the
+     CPU to apply a new frequency). This is a value in microseconds or the
+     keyword &quot;auto&quot; for autodetection.</li>
  <li><strong>-f</strong> sets the fallback frequency. In case something goes
      wrong the program sets the CPU frequency to it's minimum. In case that
      fails too it will try the fallback frequency</li>
diff --git a/argparse.c b/argparse.c
index 37d9176..124f3bc 100644
--- a/argparse.c
+++ b/argparse.c
@@ -14,6 +14,8 @@ void printhelp()
   "Usage: %s <options>\n"
   "\n"
   "Scaling options:\n"
+  "-d <delay>     Transition latency in us or \"auto\" for autodetect\n"
+  "               Default: auto\n"
   "-f <frequency> Fallback frequency in KHz, used when everything fails\n"
   "               Default: %ld\n"
   "-g <governor>  cpufreq governor to use, use \"keep\" to keep current governor\n"
@@ -65,7 +67,7 @@ void argparse(int argc, char **argv)
  memcpy(&userconfig,&config,sizeof(struct s_config));
 
 // Parse options
- while((opt=getopt(argc,argv,"c:C:f:g:hi:l:mp:s:t:u"))!=-1)
+ while((opt=getopt(argc,argv,"c:C:d:f:g:hi:l:mp:s:t:u"))!=-1)
  {
   DEBUG1_ARGPARSE("Argument: %c Value: %s\n",opt,optarg);
   switch(opt)
@@ -78,6 +80,14 @@ void argparse(int argc, char **argv)
     strncpy(userconfig.csvlog,optarg,sizeof(userconfig.csvlog));
     userconfig.csvoverwrite=1;
     break;
+   case 'd':
+    if (strcmp("auto",optarg)==0)
+    {
+     userconfig.transition_latency=-1;
+    } else {
+     userconfig.transition_latency=strtoll(optarg,NULL,10);
+    }
+    break;
    case 'f':
     userconfig.fallback_freq=strtoll(optarg,NULL,10);
     break;
diff --git a/cputemp2maxfreq.c b/cputemp2maxfreq.c
index 597f1e8..ad27062 100644
--- a/cputemp2maxfreq.c
+++ b/cputemp2maxfreq.c
@@ -29,6 +29,7 @@ struct s_config config={
  0,              // Don't overwrite CSV logfile
  NULL,           // File handler for CSV file
  0,              // Don't use unix timestamps in log outputs
+ -1,             // Transition latency, default to autodetect
 };
 struct s_cpudata cpudata;
 
@@ -38,11 +39,19 @@ void signal_handler(int signum)
  failsafe(0);
 }
 
+char *transition_latency_remarks[] = {
+ "Autodetected",
+ "Set via commandline",
+ "This seems low, consider setting it via -d"
+};
+
 int main(int argc,char **argv)
 {
  long int diff;
  long int newfreq;
 
+ char *transition_latency_remark;
+
  argparse(argc,argv);
  config.logger("%s version %s, buildtime %s %s",config.name,version(),__DATE__,__TIME__);
 
@@ -64,6 +73,12 @@ int main(int argc,char **argv)
   config.logger("Overwrite CSV log: %d",config.csvoverwrite);
  }
  config.logger("Use unix timestamps: %d",config.use_unixtime);
+ if (config.transition_latency<0)
+ {
+  config.logger("Transition latency: Autodetect");
+ } else {
+  config.logger("Transition latency: %d",config.transition_latency);
+ }
 
  if ((config.max_temp<VALID_TEMP_MIN) || (config.max_temp>VALID_TEMP_MAX))
  {
@@ -87,13 +102,21 @@ int main(int argc,char **argv)
  cpudata.min_freq=sysfs_read_long_int("/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_min_freq");
  cpudata.max_freq=sysfs_read_long_int("/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_max_freq");
  cpudata.scale_max=sysfs_read_long_int("/sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq");
- cpudata.transition_latency=sysfs_read_long_int("/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_transition_latency");
+ if (config.transition_latency<0)
+ {
+  transition_latency_remark=transition_latency_remarks[0];
+  cpudata.transition_latency=sysfs_read_long_int("/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_transition_latency");
+  if (cpudata.transition_latency<1000)  transition_latency_remark=transition_latency_remarks[2];
+ } else {
+  transition_latency_remark=transition_latency_remarks[1];
+  cpudata.transition_latency=config.transition_latency;
+ }
 
  config.logger("CPU data:");
  config.logger("Minimum frequency: %ld",cpudata.min_freq);
  config.logger("Maximum frequency: %ld",cpudata.max_freq);
  config.logger("Scaling maximum frequency: %ld",cpudata.scale_max);
- config.logger("Transition Latency: %ld",cpudata.transition_latency);
+ config.logger("Transition Latency: %ld (%s)",cpudata.transition_latency,transition_latency_remark);
 
  if ((cpudata.min_freq<VALID_FREQ_MIN) || (cpudata.min_freq>VALID_FREQ_MAX) ||
      (cpudata.max_freq<VALID_FREQ_MIN) || (cpudata.max_freq>VALID_FREQ_MAX) ||
diff --git a/cputemp2maxfreq.h b/cputemp2maxfreq.h
index afce5ca..ade4d58 100644
--- a/cputemp2maxfreq.h
+++ b/cputemp2maxfreq.h
@@ -45,6 +45,7 @@ struct s_config {
  char     csvoverwrite;    // Overwrite CSV file if it already exists
  FILE    *csvfile;         // File handle for CSV file
  char     use_unixtime;    // Use unixtime timestamps in logs and CSV
+ long int transition_latency; // User configurable transition latency, <0 for autodetect
 };
 
 #endif
-- 
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