Date: Tue, 23 Feb 2010 14:36:19 GMT From: Boris Kochergin <spawk@acm.poly.edu> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/144232: [PATCH] Add debug.cpufreq.highest to cpufreq Message-ID: <201002231436.o1NEaJDt079221@www.freebsd.org> Resent-Message-ID: <201002231440.o1NEe0Ra002633@freefall.freebsd.org>
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>Number: 144232 >Category: kern >Synopsis: [PATCH] Add debug.cpufreq.highest to cpufreq >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: change-request >Submitter-Id: current-users >Arrival-Date: Tue Feb 23 14:40:00 UTC 2010 >Closed-Date: >Last-Modified: >Originator: Boris Kochergin >Release: 8.0-RELEASE-p2 >Organization: Polytechnic Institute of NYU >Environment: FreeBSD peer 8.0-RELEASE-p2 FreeBSD 8.0-RELEASE-p2 #2: Mon Feb 22 23:18:53 EST 2010 root@peer:/usr/obj/usr/src/sys/PEER i386 >Description: I request that support for the debug.cpufreq.highest sysctl, which places an upper bound on the frequencies returned to users, be added to cpufreq. I am currently using it in conjunction with the dev.acpi_ibm.0.fan_level sysctl from the acpi_ibm module set to 0 to keep a laptop both cool and quiet while it has a broken fan. Others have also found uses for the functionality (http://forums.freebsd.org/showthread.php?t=172). >How-To-Repeat: >Fix: Patch attached with submission follows: --- sys/kern/kern_cpu.c.orig 2010-02-22 22:40:37.000000000 -0500 +++ sys/kern/kern_cpu.c 2010-02-22 23:11:03.000000000 -0500 @@ -131,12 +131,16 @@ DRIVER_MODULE(cpufreq, cpu, cpufreq_driver, cpufreq_dc, 0, 0); static int cf_lowest_freq; +static int cf_highest_freq; static int cf_verbose; TUNABLE_INT("debug.cpufreq.lowest", &cf_lowest_freq); +TUNABLE_INT("debug.cpufreq.highest", &cf_highest_freq); TUNABLE_INT("debug.cpufreq.verbose", &cf_verbose); SYSCTL_NODE(_debug, OID_AUTO, cpufreq, CTLFLAG_RD, NULL, "cpufreq debugging"); SYSCTL_INT(_debug_cpufreq, OID_AUTO, lowest, CTLFLAG_RW, &cf_lowest_freq, 1, "Don't provide levels below this frequency."); +SYSCTL_INT(_debug_cpufreq, OID_AUTO, highest, CTLFLAG_RW, &cf_highest_freq, 1, + "Don't provide levels above this frequency."); SYSCTL_INT(_debug_cpufreq, OID_AUTO, verbose, CTLFLAG_RW, &cf_verbose, 1, "Print verbose debugging messages"); @@ -306,6 +310,14 @@ goto out; } + /* Reject levels that are above our specified threshold. */ + if (cf_highest_freq > 0 && level->total_set.freq > cf_highest_freq) { + CF_DEBUG("rejecting freq %d, greater than %d limit\n", + level->total_set.freq, cf_highest_freq); + error = EINVAL; + goto out; + } + /* If already at this level, just return. */ if (CPUFREQ_CMP(sc->curr_level.total_set.freq, level->total_set.freq)) { CF_DEBUG("skipping freq %d, same as current level %d\n", @@ -633,8 +645,13 @@ continue; } - /* Skip levels that have a frequency that is too low. */ - if (lev->total_set.freq < cf_lowest_freq) { + /* + * Skip levels that have a frequency that is too low or too + * high. + */ + if (lev->total_set.freq < cf_lowest_freq || + (cf_highest_freq > 0 && + lev->total_set.freq > cf_highest_freq)) { sc->all_count--; continue; } --- share/man/man4/cpufreq.4.orig 2010-02-23 09:24:45.000000000 -0500 +++ share/man/man4/cpufreq.4 2010-02-23 09:25:59.000000000 -0500 @@ -98,6 +98,11 @@ This setting is also accessible via a tunable with the same name. This can be used to disable very low levels that may be unusable on some systems. +.It Va debug.cpufreq.highest +Highest CPU frequency in MHz to offer to users. +This setting is also accessible via a tunable with the same name. +This can be used to disable very high levels that may be unusable on +some systems. .It Va debug.cpufreq.verbose Print verbose messages. This setting is also accessible via a tunable with the same name. >Release-Note: >Audit-Trail: >Unformatted:
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