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diff --git a/README.html b/README.html new file mode 100644 index 0000000..494a75d --- /dev/null +++ b/README.html @@ -0,0 +1,115 @@ +<h1>cputemp2maxfreq</h1> +<p> + This daemon sets the cpufreq scale_max_freq setting and scales it down when + the CPU reaches a given temperature. +</p> +<h2>Why this program?</h2> +<p> + I recently bought a new mainboard, an <a href="https://www.asrock.com/mb/Intel/J5040-ITX/">Asrock J5040-ITX</a>. + This board has a passively cooled CPU which means heat can build up when you + give it a GPU or CPU intensive task. It will happily heat itself up to over + 95°C, and since i'm a Gentoo user, that happens quite a lot :-). I thought + it's wasn't a good idea to leave it running for hours at 95°C. One + solution could be to add a small fan, but I hate fans and that's why i got a + fanless mainboard in the first place. The other solution is to reduce CPU heat + generation when the temperature is too high, and the best way to do that is to + reduce it's frequency as can be done with cpufreq within linux.<br> + When discovered there is no program to do that i deciced to write it myself. +</p> +<h2>What does this program do?</h2> +<p> + It's basic function is simple: It reads the CPU's temperature sensor and if + the temperature is above a certain threshold it will lower scale_max_freq to + lower the CPU speed and allow it to cool down. When the temperature drops + below the threshold it will increase scalea_max_freq again to allow it to + reach it's full speed. +</p> +<p> + There is a lot you can tune and do with this basic function, these are the + options you can pass to cputemp2maxfreq: +</p> +<ul> + <li><strong>-c or -C</strong> will log data to a CSV file which can be used + for analysis later. See the paragraph below on how to use it with + LibreOffice. -c will append data, -C will overwrite an existing file</li> + <li><strong>-f</strong> sets the fallback frequency. In case something goes + wrongthe program sets the CPU frequency to it's minimum. In case that + fails too it will try the fallback frequency</li> + <li><strong>-g</strong> the cpufreq governor to use. Conservative seems to work + nicely with this daemon's concept. Use the special keyword + "keep" to prevent this daemon from changing the governor</li> + <li><strong>-i</strong> set the file for CPU temperature readout. Most sensors + should be available in sysfs somewhere</li> + <li><strong>-l</strong> set the logging mechanism to use. Possible values: + <ul> + <li><strong>none</strong>: No logging at all</li> + <li><strong>kmsg</strong>: Log to the kernel log so you can see it with dmesg</li> + <li><strong>stdout</strong>: Log to stdout, especially useful when testing/tuning</li> + <li><strong>syslog</strong>: Log to syslog, it will use facility Daemon and level Critical</li> + </ul></li> + <li><strong>-m</strong> log measurements (CPU temperature and frequency)</li> + <li><strong>-p</strong> set poll interval</li> + <li><strong>-s</strong> set the step size to increase/decrease CPU speed. + Note that this value will be multiplied by the difference between the CPU + temperature and the set temperature to calculate the actual change.</li> + <li><strong>-t</strong> set the temperature limit</li> +</ul> +<p> + To use the CSV file with libreOffice first stop the daemon to make sure all + data has been written. Then use LibreOffice Calc to open the CSV file. In the + text import dialog use the following options: +</p> +<ul> + <li>Separated by Comma</li> + <li>String delimited: "</li> + <li>Other options: Only set Detect special numbers, other options should be disabled</li> +</ul> +<p> + The preview should already show a nicely formed table, so click Ok. +</p> +<p> + If the document is opened read-only, click the Edit Document button. Select + the whole sheet, open the Insert menu and choose Chart... +</p> +<p> + Now select Chart Type XY (Scatter) and subtype Lines Only and click Finish. +</p> +<p> + You should now have a graph and depending on the number of data points it + might beusefull to make it wider to give the graph some more space. Becaue + the CPU temperatures are much lower numbers than the frequencies it's useful + to add a second Y axis, to do so click on the background and choose + Insert/Delete axes and enable the secondary Y axis. Now click the first + temperature line (usually at the bottom of the chart) and choose Format Data + Series, and set Allign Data Series to Secondary Y axis. Do the same for the + second temperature line. +</p> +<p>The resulting graph should look like this:</p> +<img src="lo_graph_example.png"> +<p> + You can clearly see the scaling this daemon does between 12:37:26 and 12:40:19. +</p> +<h2>How to install this program</h2> +<p> + Since i'm a Gentoo user i made an ebuild provided in the gentoo directory of + the source code. Place it in your own overlay to use it, the suggested + category is sys-power. The ebuild will install the binary in /usr/sbin and + install an initscript so you can start the daemon on boot. +</p> +<p> + To install from source manually the best way is to <strong>git clone + https://code.pa4wdh.nl.eu.org/tools/cputemp2maxfreq</strong>. Change to the + source directory and type <strong>make</strong> to start the build proces. It + shouldn't take long since this is a very small program. The result should + be an executable called cputemp2maxfreq. +</p> +<h2>What can i do with this program?</h2> +<p> + The daemon has two uses: Get the maximum performance from your CPU when the + temperature allows it, and protect the hardware from overheating. +</p> +<p> + Since i'm a Gentoo user there is a topic about this program on thei + <a href="https://forums.gentoo.org/viewtopic-t-1163405.html">Gentoo forums</a>. +</p> +<p>Happy computing!</p> |