Re: [libvirt] [PATCH 1/2] Get cpuMhz of virNodeGetInfo() from cpufreq/cpuinfo_max_freq, if exist

Hi, Eric On Tue, 1 Feb 2011 10:26:36 +0900 Minoru Usui <usui(a)mxm.nes.nec.co.jp&gt; wrote: > Hi, Eric > > On Mon, 31 Jan 2011 15:46:39 -0700 > Eric Blake <eblake(a)redhat.com&gt; wrote: > > > On 01/27/2011 02:51 AM, Minoru Usui wrote: > > > virNodeGetInfo() gets from > > > /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq, first. > > > > > > Signed-off-by: Minoru Usui <usui(a)mxm.nes.nec.co.jp&gt; > > > > I haven't looked closely at this series yet... > > > > > +    /* > > > +     * nodeinfo->mhz should return maximum frequency, > > > +     * but "cpu MHz" of /proc/cpuinfo is scaled by power saving feature. > > > +     * So it gets cpufreq/cpuinfo_max_freq, if possible. > > > +     */ > > > +    ret = get_cpu_value(0, "cpufreq/cpuinfo_max_freq", true); > > > +    if (ret < 0) > > > + return -1; > > > +    else if (ret != 1) { > > > + /* convert unit */ > > > + cpu_mhz = ret / 1000; > > > > But which units is this converting between, and should it truncate or > > round up? > > I think it divide by 1000 is collect, because my machine returns below values. > > ----------------------------------------------------------------- > # cat /sys/devices/system/cpu/cpu?/cpufreq/cpuinfo_max_freq > 2333331 > 2333331 > 2333331 > 2333331 > 2333331 > 2333331 > 2333331 > 2333331 > > # grep 'cpu MHz' /proc/cpuinfo > cpu MHz         : 2333.331 > cpu MHz         : 2333.331 > cpu MHz         : 2333.331 > cpu MHz         : 2333.331 > cpu MHz         : 2333.331 > cpu MHz         : 2333.331 > cpu MHz         : 2333.331 > cpu MHz         : 2333.331 > ----------------------------------------------------------------- > > On the other hand, I don't have clear opinion about truncate or round up. > Present implementation of linuxNodeInfoCPUPopulate() selects truncate, > so I implement to truncate logic. Are my explanations enough? If not or I'm misunderstanding something, please let me know.