Re: [libvirt] [PATCH 1/2] Get cpuMhz of virNodeGetInfo() from cpufreq/cpuinfo_max_freq, if exist
Hi, Eric
On Mon, 31 Jan 2011 15:46:39 -0700
Eric Blake <eblake(a)redhat.com> 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>
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.
--
Minoru Usui <usui(a)mxm.nes.nec.co.jp>