From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: Re: Overall picture of cpufreq.. Date: Mon, 14 Jan 2008 11:16:53 +0100 Message-ID: <478B3695.1030406@wpkg.org> References: <9f79f7f50801111415w354dc91fwfeec98b16a00fb74@mail.gmail.com> <1200264884.4157.16.camel@queen> <9f79f7f50801131812x6a68c202tb4c25fa2116b32e4@mail.gmail.com> <478B0A82.6050503@wpkg.org> <1200304310.23376.311.camel@queen.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1200304310.23376.311.camel@queen.suse.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: cpufreq-bounces@lists.linux.org.uk Errors-To: cpufreq-bounces+glkc-cpufreq=m.gmane.org+glkc-cpufreq=m.gmane.org@lists.linux.org.uk To: trenn@suse.de Cc: Martin.Leisner@xerox.com, cpufreq@lists.linux.org.uk Thomas Renninger schrieb: > On Mon, 2008-01-14 at 08:08 +0100, Tomasz Chmielewski wrote: (...) >> It looks to me that ondemand governor doesn't have "the complete >> intelligence". >> >> For example, it doesn't detect CPU load coming from some kernel tasks, >> like kcryptd: reads/writes from a device crypted with dm-crypt will be >> very slow if one uses the ondemand governor, as CPU speed will always be >> set to the lowest possible (so there is not enough power to >> crypt/decrypt data). >> >> Ironically, this is the only case when starting bzip2 will speed up your >> disk access... Or, use a userspace governor. >> >> >> See also http://bugzilla.kernel.org/show_bug.cgi?id=9729 > > I don't know about this one. > AFAIK there has been some work done there, I expect the bug in the > crypto area, not in cpufreq/ondemand layer. > > A Xeon processor stepped down from 2800 to 350 looks bogus (maybe the > new ones even can, not sure) Quite the contrary - it's a pretty old Xeon which is i386 only. Why does it look bogus to you, anyway? > could it be that you are using > p4-clockmode driver which is doing throttling, not frequency scaling, > better try with acpi-cpufreq then. Indeed, I am using p4-clockmod. acpi-cpufreq doesn't work for me on that machine (p4-clockmod not loaded when I try to insert acpi-cpufreq): # modprobe acpi-cpufreq FATAL: Error inserting acpi_cpufreq (/lib/modules/2.6.23.12-pata-1/kernel/arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.ko): No such device -- Tomasz Chmielewski http://wpkg.org