On Fri, 27 May 2011 22:33:00 +0800 Daniel Veillard <veillard@redhat.com> wrote:
On Fri, May 27, 2011 at 02:34:50PM +0100, Daniel P. Berrange wrote:
On Wed, May 25, 2011 at 03:01:29PM +0900, Minoru Usui wrote:
Hi,
This is v6 of virNodeGetCPUTimeParameters() API. (This time, I rename it to virNodeGetCPUStats()) It returns cpu utilization or cumulative cpu time of the node from /proc/stat since node boots up. This patch only supports linux host.
The code in this patch series looks fine to me now. I would ACK the whole series, but I have one design question I should have asked previously.
This API returns CPU information for the host as a whole. Historically, when adding an API like this, someone has always then asked for a per-CPU breakdown of the same data.
So I wonder if we should add a parameter for the CPU num to the API:
int virNodeGetCPUStats (virConnectPtr conn, int cpuNum, virCPUStatsPtr params, int *nparams, unsigned int flags);
And have a constant for getting the host data as a whole:
#define VIR_NODE_CPU_STATS_ALL_CPUS -1
so if you want to get individual data for each CPU you can do
virNodeGetCPUStats(conn, 0, params, nparams, flags); virNodeGetCPUStats(conn, 1, params, nparams, flags); virNodeGetCPUStats(conn, 2, params, nparams, flags); virNodeGetCPUStats(conn, 3, params, nparams, flags);
But if you just want the data for the host as a whole you can do
virNodeGetCPUStats(conn, VIR_NODE_CPU_STATS_ALL_CPUS, params, nparams, flags);
The /proc/stat file already has the data we need for both these styles
$ grep cpu /proc/stat cpu 2632143 17400 1341532 32819705 1177560 674 21606 0 11997 0 cpu0 1263069 9280 596278 16274365 620428 631 17303 0 6131 0 cpu1 1369073 8119 745254 16545339 557131 43 4302 0 5865 0
Agreed, similary as for the virNodeGetMemoryStats() patch set, the patches looks good enough for being applied but doing the suggested changes (i.e. adding a new argument for the cpu number or the cell number). For virsh command I would make querying all the default but just add an optionnal argument --cpu virsh nodecpustats --cpu cpunumber and similary on the memry patch set add an optional --cell argument virsh nodememstats --cell cellnumber
That way the API and virsh command are ready for more precise use and we won't need to make a second set of APIs.
thanks !
OK. I'll add cpu/cell argments for more generalization.
Daniel -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel@veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/
-- Minoru Usui <usui@mxm.nes.nec.co.jp>