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--- en:c2_set_cpu_freq [2016/09/05 15:56]
joy.cho [How to set max cpu frequency and cores]
+++ en:c2_set_cpu_freq [2017/07/20 09:41] (current)
joy.cho [How to set max cpu frequency]
@@ Line 2: / Line 2: @@
 <WRAP center round important>
-  * Ubuntu
+  * Ubuntu : Available with 3.14.77-80 (Sep 8, 2016) or higher version
-  * Android
+  * Android : Available with Android v2.2 or higher version
 </WRAP>
+For further information, you can refer to the following forum thread.
+http://forum.odroid.com/viewtopic.php?f=141&t=23044
 ===== How to set max cpu frequency =====
-Let's talk about the detailed descriptions and examples of modeline information here.
+Here are the available cpu frequency sets and you can set one of them as max. cpu frequency using boot.ini
+== The available list of cpu frequency set ==
+Here are the common sets we recommend under normal conditions.
+|  frequency  |  notation on boot.ini  |
+|  1.656 GHz  |  "1656"  |
+|  1.536 GHz  |  "1536"  |
+|  1.296 GHz  |  "1296"  |
+|  1 GHz  |  "1000"  |
+|  500 MHz  |  "500"  |
+|  250 MHz  |  "250"  |
+|  100 MHz  |  "100"  |
+There are some advanced frequency sets you can try below.
+The following sets are unstable with 2 or more cpu-cores so, you should adjust cpu cores as described the next section.
+|  frequency  |  notation on boot.ini  |  note  |
+|  1.680 GHz  |  "1680"   | booting OK with 4 cores / recommend 3 cores for heavy load test  |
+|  1.752 GHz  |  "1752"   | booting OK with 4 cores / recommend 2 cores for heavy load test  |
+|  1.896 GHz  |  "1896"  | booting OK with 1~3 cores / recommend running with a single core  |
+|  1.920 GHz  |  "1920"  | booting OK with 1 or 2 cores / recommend running with a single core  |
+|  1.944 GHz  |  "1944"  | booting OK with a single core but unstable |
+|  2.016 GHz  |  "2016"  | extremely unstable  |
+== setting boot.ini ==
+Please modify **max_freq ** based on the aforementioned frequency table. The unit of max_freq in boot.ini is MHz.
+If you don't set max_freq in bootargs or the setting value is wrong one which doesn't exist in frequency table, max_freq will be set as "1.536GHz" by default.
+<code>
+### boot.ini
+# max cpu frequency in dvfs table / in MHz unit
+# setenv max_freq "2016"  # 2.016GHz
+# setenv max_freq "1944"  # 1.944GHz
+# setenv max_freq "1920"  # 1.920GHz
+# setenv max_freq "1896"  # 1.896GHz
+# setenv max_freq "1752"  # 1.752GHz
+# setenv max_freq "1680"  # 1.680GHz
+# setenv max_freq "1656"  # 1.656GHz
+setenv max_freq "1536"  # 1.536GHz
+# Boot Arguments
+# add max_freq in bootargs
+setenv bootargs "root=UUID=e139ce78-9841-40fe-8823-96a304a09859 rootwait ro ${condev} no_console_suspend max_freq=${max_freq} hdmimode=${m} ${comde} m_bpp=${m_bpp} vout=${vout} fsck.repair=yes net.ifnames=0 elevator=noop disablehpd=${hpd}"
+</code>
+After setting it, then be sure you do reboot.
+You can check the frequency list as following.
+ex) setenv max_freq "1656"
+<code>
+root@odroid64:~# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
+250000 500000 1000000 1296000 1536000 1656000
+</code>
+===== How to set the number of cpu cores  =====
+Also, you can set cpu-cores you want to activate using boot.ini
+The available range is "1" to "4"
+== setting boot.ini ==
+<code>
+### boot.ini
+# max cpu-cores
+# setenv maxcpus "1"
+# setenv maxcpus "2"
+# setenv maxcpus "3"
+setenv maxcpus "4"
+# Boot Arguments
+# add max_freq in bootargs
+setenv bootargs "root=UUID=e139ce78-9841-40fe-8823-96a304a09859 rootwait ro ${condev} no_console_suspend max_freq=${max_freq} maxcpus=${maxcpus} hdmimode=${m} ${comde} m_bpp=${m_bpp} vout=${vout} fsck.repair=yes net.ifnames=0 elevator=noop disablehpd=${hpd}"
+</code>
+After setting it, then please be sure you do reboot.
+You can check the activated cpu cores as following.
+ex) setenv maxcpus "2"
+<code>
+root@odroid64:~# cat /sys/devices/system/cpu/online
+-1
+root@odroid64:~# cat /sys/devices/system/cpu/offline
+-3
+</code>
-* The available list of cpu frequency set
+<code>
+root@odroid64:~# cat /proc/cpuinfo
+processor       : 0
+BogoMIPS        : 2.00
+Features        : fp asimd crc32
+CPU implementer : 0x41
+CPU architecture: 8
+CPU variant     : 0x0
+CPU part        : 0xd03
+CPU revision    : 4
-| frequency | notation on boot.ini | note |
+processor       : 1
-|  |  |  |
+BogoMIPS        : 2.00
-|  |  | 1344 |
+Features        : fp asimd crc32
-| pixel_clock  | pixel clock   | 148.50 MHz  | 204.8 MHz |
+CPU implementer : 0x41
-| hor_freq   | horizontal frequency   | 67.5 kHz | 83.66 kHz |
+CPU architecture: 8
-| ver_freq   | vertical frequency   | 60 Hz  | 60 Hz |
+CPU variant     : 0x0
+CPU part        : 0xd03
+CPU revision    : 4
+Hardware        : ODROID-C2
+</code>