intel_lpmd[4038]: Open /proc/sys/kernel/sched_itmt_enabled failed in 6.12 kernel

[user7z]

● intel_lpmd.service - Intel Linux Energy Optimizer (lpmd) Service
Loaded: loaded (/usr/lib/systemd/system/intel_lpmd.service; enabled; preset: disabled)
Active: active (running) since Mon 2024-11-25 13:17:11 +01; 12s ago
Invocation: c820f3ea5eb845c999bab3eeef8a988b
Main PID: 4038 (intel_lpmd)
Tasks: 6 (limit: 38001)
Memory: 1.2M (peak: 2.7M)
CPU: 28ms
CGroup: /system.slice/intel_lpmd.service
└─4038 /usr/bin/intel_lpmd --systemd --dbus-enable

Nov 25 13:17:11 lp systemd[1]: Starting Intel Linux Energy Optimizer (lpmd) Service...
Nov 25 13:17:11 lp intel_lpmd[4038]: Looking for config file /etc/intel_lpmd/intel_lpmd_config_F6_M154_T15.xml
Nov 25 13:17:11 lp intel_lpmd[4038]: Looking for config file /etc/intel_lpmd/intel_lpmd_config_F6_M154.xml
Nov 25 13:17:11 lp intel_lpmd[4038]: Reading configuration file /etc/intel_lpmd/intel_lpmd_config.xml
Nov 25 13:17:11 lp intel_lpmd[4038]: Open /proc/sys/kernel/sched_itmt_enabled failed
Nov 25 13:17:11 lp systemd[1]: Started Intel Linux Energy Optimizer (lpmd) Service.

thats error didnt showed before 6.12 kernel , & why those meteor lake configs in my alderlake platform ? even thogh i delete them , the daemon still search for them !! , is this a normal behaviour ? , what i would expect is to autodiscover the cpu in use & apply its correspounding config.

[zhang-rui]

Does this file "/proc/sys/kernel/sched_itmt_enabled" exist on your platform?

[zhang-rui]

and what platform is this?

[zhang-rui]

BTW, are you running lpmd with HT enabled or disabled?

[user7z]

@zhang-rui
platform : i5-1235-U (alderlake-U)
file existence : the file doesnt exist.
my config:
<Configuration> <Mode>0</Mode> <PerformanceDef>-1</PerformanceDef> <BalancedDef>0</BalancedDef> <PowersaverDef>1</PowersaverDef> <HfiSuvEnable>1</HfiSuvEnable> <util_entry_threshold>15</util_entry_threshold> <util_exit_threshold>90</util_exit_threshold> <EntryDelayMS>0</EntryDelayMS> <ExitDelayMS>0</ExitDelayMS> <EntryHystMS>0</EntryHystMS> <ExitHystMS>0</ExitHystMS> <IgnoreITMT>0</IgnoreITMT> <States> <CPUFamily> 6 </CPUFamily> <CPUModel> 154 </CPUModel> <CPUConfig> 2P8E-15W </CPUConfig> </States> </Configuration>
service log :

● intel_lpmd.service - Intel Linux Energy Optimizer (lpmd) Service
Loaded: loaded (/usr/lib/systemd/system/intel_lpmd.service; enabled; preset: disabled)
Active: active (running) since Tue 2024-11-26 07:27:42 +01; 16min ago
Invocation: 403a0241a096448b9bbe72d005acdfb8
Main PID: 2183 (intel_lpmd)
Tasks: 5 (limit: 38001)
Memory: 32.2M (peak: 32.2M)
CPU: 50ms
CGroup: /system.slice/intel_lpmd.service
└─2183 /usr/bin/intel_lpmd --systemd --dbus-enable

Nov 26 07:27:35 lp systemd[1]: Starting Intel Linux Energy Optimizer (lpmd) Service...
Nov 26 07:27:35 lp intel_lpmd[2183]: Looking for config file /etc/intel_lpmd/intel_lpmd_con>
Nov 26 07:27:35 lp intel_lpmd[2183]: Looking for config file /etc/intel_lpmd/intel_lpmd_con>
Nov 26 07:27:35 lp intel_lpmd[2183]: Reading configuration file /etc/intel_lpmd/intel_lpmd_>
Nov 26 07:27:35 lp intel_lpmd[2183]: Open /proc/sys/kernel/sched_itmt_enabled failed
Nov 26 07:27:42 lp systemd[1]: Started Intel Linux Energy Optimizer (lpmd) Service.

[zhang-rui]

please paste the lscpu output of this platform.

[user7z]

lscpu output

the PKGBUILD

[phush0]

same here for 7155H laptop + arch linux

[phush0]

well with this patch https://lore.kernel.org/lkml/173693263689.31546.15174865187592950218.tip-bot2@tip-bot2/ it was moved from /proc/sys/kernel/sched_itmt_enabled to /sys/kernel/debug/x86/sched_itmt_enabled pls fix. Also it is not int any more but rather Y or N, so that have to be fixed also

[jwarp-riglr]

Can confirm it's at /sys/kernel/debug/x86/sched_itmt_enabled with a Y/N for me.

[norbusan]

What about that?

diff --git a/src/include/lpmd.h b/src/include/lpmd.h
index a6414c1..a0009b9 100644
--- a/src/include/lpmd.h
+++ b/src/include/lpmd.h
@@ -363,6 +363,8 @@ int lpmd_write_str_append(const char *name, char *str, int print_level);
 int lpmd_write_int(const char *name, int val, int print_level);
 int lpmd_open(const char *name, int print_level);
 int lpmd_read_int(const char *name, int *val, int print_level);
+int lpmd_read_yn(const char *name, int *val, int print_level);
+int lpmd_write_yn(const char *name, int val, int print_level);
 char* get_time(void);
 void time_start(void);
 char* time_delta(void);
diff --git a/src/lpmd_helpers.c b/src/lpmd_helpers.c
index b85c9b3..eb0da93 100644
--- a/src/lpmd_helpers.c
+++ b/src/lpmd_helpers.c
@@ -207,6 +207,79 @@ int lpmd_read_int(const char *name, int *val, int print_level)
 
 }
 
+int lpmd_write_yn(const char *name, int val, int print_level)
+{
+   char str[5];
+
+   if (!name)
+       return 0;
+
+   int chars_written = snprintf(str, 4, "%d", val);
+   if (chars_written < 0) {
+       return 1;
+   }
+
+   return _write_str (name, str, print_level, 2, "r+");
+}
+
+int lpmd_read_yn(const char *name, int *val, int print_level)
+{
+   FILE *filep;
+   char prefix[16];
+   int i, ret;
+
+   if (!name || !val)
+       return 1;
+
+   if (print_level >= 15)
+       return 1;
+
+   if (print_level < 0) {
+       prefix[0] = '\0';
+   }
+   else {
+       for (i = 0; i < print_level; i++)
+           prefix[i] = '\t';
+       prefix[i] = '\0';
+   }
+
+   filep = fopen (name, "r");
+   if (!filep) {
+       lpmd_log_error ("%sOpen %s failed\n", prefix, name);
+       return 1;
+   }
+
+   ret = fgetc(filep);
+   if (ret == EOF) {
+       if (feof(filep)) {
+           lpmd_log_error ("%sRead %s failed due to EOF\n", prefix, name);
+       } else if (ferror(filep)) {
+           lpmd_log_error ("%sRead %s failed, error %s\n", prefix, name, strerror(errno));
+       }
+       fclose (filep);
+       return 1;
+   }
+
+   fclose (filep);
+
+   if (ret == 'Y') {
+       *val = 1;
+   } else if (ret == 'N') {
+       *val = 0;
+   } else {
+       lpmd_log_error ("%sRead %s failed, read %c\n", prefix, name, ret);
+       return 1;
+   }
+
+
+   if (print_level >= 0)
+       lpmd_log_debug ("%sRead \"%c\" from %s\n", prefix, *val, name);
+
+   return 0;
+
+}
+
+
 /*
  * lpmd_open does not require print on success
  * print_level: -1: don't print on error
diff --git a/src/lpmd_proc.c b/src/lpmd_proc.c
index 64220f7..376a774 100644
--- a/src/lpmd_proc.c
+++ b/src/lpmd_proc.c
@@ -142,7 +142,7 @@ int get_util_exit_hyst(void)
 }
 
 /* ITMT Management */
-#define PATH_ITMT_CONTROL "/proc/sys/kernel/sched_itmt_enabled"
+#define PATH_ITMT_CONTROL "/sys/kernel/debug/x86/sched_itmt_enabled"
 
 static int saved_itmt = SETTING_IGNORE;
 static int lp_mode_itmt = SETTING_IGNORE;
@@ -161,13 +161,13 @@ int get_itmt(void)
 {
    int val;
 
-   lpmd_read_int(PATH_ITMT_CONTROL, &val, -1);
+   lpmd_read_yn(PATH_ITMT_CONTROL, &val, -1);
    return val;
 }
 
 static int init_itmt(void)
 {
-   return lpmd_read_int(PATH_ITMT_CONTROL, &saved_itmt, -1);
+   return lpmd_read_yn(PATH_ITMT_CONTROL, &saved_itmt, -1);
 }
 
 static int process_itmt(void)
@@ -182,7 +182,7 @@ static int process_itmt(void)
 
    lpmd_log_debug ("%s ITMT\n", lp_mode_itmt ? "Enable" : "Disable");
 
-   return lpmd_write_int(PATH_ITMT_CONTROL, lp_mode_itmt, -1);
+   return lpmd_write_yn(PATH_ITMT_CONTROL, lp_mode_itmt, -1);
 }
 
 /* Main functions */

At least the daemon booted and didn't complain.

[zhang-rui]

Problem should be fixed in the latest code.
Please reopen this ticket if the problem is still in the latest main branch.

[phush0]

Problem persists with the latest code too, path is same and will not work on latest kernels. I do not have permition to reopen the ticket.

● intel_lpmd.service - Intel Linux Energy Optimizer (lpmd) Service
     Loaded: loaded (/usr/lib/systemd/system/intel_lpmd.service; enabled; preset: disabled)
     Active: active (running) since Wed 2025-05-28 09:44:57 EEST; 2s ago
 Invocation: b2706ff4168546a4a2742364fccb2820
       Docs: man:intel_lpmd(8)
   Main PID: 38232 (intel_lpmd)
      Tasks: 6 (limit: 37799)
     Memory: 1.4M (peak: 2.3M)
        CPU: 20ms
     CGroup: /system.slice/intel_lpmd.service
             └─38232 /usr/bin/intel_lpmd --systemd --dbus-enable

май 28 09:44:57 da-laptop systemd[1]: Starting Intel Linux Energy Optimizer (lpmd) Service...
май 28 09:44:57 da-laptop intel_lpmd[38232]: Looking for config file /etc/intel_lpmd/intel_lpmd_config_F6_M170_T28.xml
май 28 09:44:57 da-laptop intel_lpmd[38232]: Looking for config file /etc/intel_lpmd/intel_lpmd_config_F6_M170.xml
май 28 09:44:57 da-laptop intel_lpmd[38232]: Open /proc/sys/kernel/sched_itmt_enabled failed
май 28 09:44:57 da-laptop systemd[1]: Started Intel Linux Energy Optimizer (lpmd) Service.

[zhang-rui]

This one is normal.
I have added code to detect this failure during probe and stop accessing this attribute anymore when it is not available.

[zhang-rui]

BTW, I don't think it is a good idea to access any debugfs attribute as it is not ABI.