Hi, I just realized that I just replied to Jean, and didn't reply-all previously. I am using 2.6.39-020639-generic kernel and I am running Ubuntu 9.04. I couldn't find /etc/sensors.d/coretemp.config file. I am using 3450S intel i5 processor, which has Tjmax of 103C (sorry for the typo in my original email), based on http://users.sosdg.org/~qiyong/lxr/source/Documentation/hwmon/coretemp?a=um . I found that for some processors, IA32_TEMPERATURE_TARGET MSR has the Tjmax value; I assume that the coretemp.c tries to read this register and if it doesn't succeed then, it uses the heuristic value. Few other doubts I have are: 1) For a multi-core processor, are there separate Tjmax for each core or just 1 Tjmax value per processor? 2) Inside coretemp.c file, the temperature is read in milli-degree C, and multiplied by 1000 to get C value. Does it mean that DTS value stored in IA32_ThERMAL_STATUS MSR is in milli-degrees? I also notice that there are only 7 bits assigned to DTS value, which would not be sufficient to cover the wide range of temperate values if it is in mill-degree C. Am I missing something here? Thanks, Kapil On Jul 21, 2013, at 3:40 AM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > On Fri, Jul 19, 2013 at 05:47:24PM +0200, Jean Delvare wrote: >> Hi Kapil, >> >> On Fri, 19 Jul 2013 11:28:28 -0400, Kapil Dev wrote: >>> I have a couple of queries about lm-sensors package. >>> >>> 1) The FAQ section in chapter-1 says that the drivers update their values every 1 sec. I am aware of the fact that reading the sensors more frequently will affect the performance as it is intrusive to CPU to read an MSR, but I need to read the core-temperature values at faster rate for a project. Would you tell me what changes I should make to read the sensors faster? In particular, I want to read the core temperature (I believe it is done in coretemp.c through IA32_THERMAL_STATUS MSR register). coretemp.c seems to have "jiffy" as time stamp, if I change it in the coretemp.c, will it work? Or, is there any other file that needs to be changed during kernel-compilation? >> >> Just change this condition in show_temp(): >> >> /* Check whether the time interval has elapsed */ >> if (!tdata->valid || time_after(jiffies, tdata->last_updated + HZ)) { >> >> to just: >> >> /* Always update */ >> if (1) { >> >> This will let you read the value as frequently as you want. Or if you >> want to keep a safety guard, you can simply change HZ to HZ/10 (read >> every 0.1 s max) or HZ/100 (read every 0.01 s max.) >> >>> 2) Does the lm-sensor package use the correct value of Tjmax (the temp value at which PROCHOT signal goes high) automatically based on the processor brand and type? I noticed that the Tjmax =100C is used in core temp.c, but the 22nm intel processor that I am working on has Tjmax of 105C. Do I need to change it myself? >> >> We have a complex heuristic to figure out the right TjMax value, but >> Intel made it such a mess that it is very difficult. So it really is >> best effort. If the driver has TjMax wrong for your CPU, please let us >> know what kernel version you are running, what CPU model you have is >> and where you found the correct TjMax value. >> > The 22nm processors should all report it correctly from CPU registers, > so this is really odd. My IvyBridge CPU (i7-3770K) reports it correctly. > I am quite sure the Haswell did too, but I am some 12,000 miles away > from it and the system is shut down, so we'll have to wait for another > 10 days or so until I can check it. > > So, yes, we'll definitely need the CPU model and kernel version. > > Guenter > >> Then you can either try to fix it in the driver itself, or adjust it >> from userspace by adding this to /etc/sensors.d/coretemp.conf: >> >> chip "coretemp-*" >> >> compute temp1 @+5, @-5 >> compute temp2 @+5, @-5 >> compute temp3 @+5, @-5 >> compute temp4 @+5, @-5 >> compute temp5 @+5, @-5 >> >> (Adjust for your own case...) >> >> Hope that helps, >> -- >> Jean Delvare >> http://khali.linux-fr.org/wishlist.html >> >> _______________________________________________ >> lm-sensors mailing list >> lm-sensors@xxxxxxxxxxxxxx >> http://lists.lm-sensors.org/mailman/listinfo/lm-sensors >> _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
