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Re: [libvirt] [PATCH 03/12] [v7] virNodeGetCPUTime: Implement public API



On Tue, Jun 07, 2011 at 10:00:23AM +0900, Minoru Usui wrote:
> virNodeGetCPUTime: Implement public API
> 
> Signed-off-by: Minoru Usui <usui mxm nes nec co jp>
> ---
>  src/libvirt.c |   91 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 91 insertions(+), 0 deletions(-)
> 
> diff --git a/src/libvirt.c b/src/libvirt.c
> index eaae0ec..45d9be7 100644
> --- a/src/libvirt.c
> +++ b/src/libvirt.c
> @@ -5338,6 +5338,97 @@ error:
>  }
>  
>  /**
> + * virNodeGetCPUStats:
> + * @conn: pointer to the hypervisor connection.
> + * @cpuNum: number of node cpu. (VIR_CPU_STATS_ALL_CPUS means total cpu 
> + *          statistics)
> + * @params: pointer to node cpu time parameter objects
> + * @nparams: number of node cpu time parameter (this value should be same or
> + *          less than the number of parameters supported)
> + * @flags: currently unused, for future extension. always pass 0.
> + *
> + * This function provides individual cpu statistics of the node.
> + * If you want to get total cpu statistics of the node, you must specify
> + * VIR_CPU_STATS_ALL_CPUS to @cpuNum.
> + * The @params array will be filled with the values equal to the number of
> + * parameters suggested by @nparams
> + *
> + * As the value of @nparams is dynamic, call the API setting @nparams to 0 and
> + * @params as NULL, the API returns the number of parameters supported by the
> + * HV by updating @nparams on SUCCESS. The caller should then allocate @params
> + * array, i.e. (sizeof(@virCPUStats) * @nparams) bytes and call
> + * the API again.
> + *
> + * Here is the sample code snippet:
> + *
> + * if ((virNodeGetCPUStats(conn, cpuNum, NULL, &nparams, 0) == 0) &&
> + *     (nparams != 0)) {
> + *     params = vshMalloc(ctl, sizeof(virCPUStats) * nparams);
> + *     memset(params, 0, sizeof(virCPUStats) * nparams);
> + *     if (virNodeGetCPUStats(conn, cpuNum, params, &nparams, 0)) {
> + *         vshError(ctl, "%s", _("Unable to get node cpu stats"));
> + *         goto error;
> + *     }
> + * }

The example code should stick to using standard libc APIs for
demonstration purposes, because applications developing against
libvirt don't have use of vshMalloc or vshError. Just use normal
malloc() and fprintf(stderr) here instead.


> + *
> + * This function doesn't requires privileged access to the hypervisor.
> + * This function expects the caller to allocate the @params.
> + *
> + * CPU time Statistics:
> + *
> + * VIR_NODE_CPU_STATS_KERNEL:
> + *     The cumulative CPU time which spends by kernel,
> + *     when the node booting up.(nanoseconds)
> + * VIR_NODE_CPU_STATS_USER:
> + *     The cumulative CPU time which spends by user processes,
> + *     when the node booting up.(nanoseconds)
> + * VIR_NODE_CPU_STATS_IDLE:
> + *     The cumulative idle CPU time, when the node booting up.(nanoseconds)
> + * VIR_NODE_CPU_STATS_IOWAIT:
> + *     The cumulative I/O wait CPU time, when the node booting up.(nanoseconds)
> + * VIR_NODE_CPU_STATS_UTILIZATION:
> + *     The CPU utilization. The usage value is in percent and 100%
> + *     represents all CPUs on the server.
> + *
> + * Returns -1 in case of error, 0 in case of success.
> + */
> +int virNodeGetCPUStats (virConnectPtr conn,
> +                        int cpuNum,
> +                        virCPUStatsPtr params,
> +                        int *nparams, unsigned int flags)
> +{
> +    VIR_DEBUG("conn=%p, cpuNum=%d, params=%p, nparams=%d, flags=%u",
> +              conn, cpuNum, params, nparams ? *nparams : -1, flags);
> +
> +    virResetLastError();
> +
> +    if (!VIR_IS_CONNECT(conn)) {
> +        virLibConnError(VIR_ERR_INVALID_CONN, __FUNCTION__);
> +        virDispatchError(NULL);
> +        return -1;
> +    }
> +
> +    if ((nparams == NULL) || (*nparams < 0) ||
> +        ((cpuNum < 0) && (cpuNum != VIR_CPU_STATS_ALL_CPUS))) {
> +        virLibConnError(VIR_ERR_INVALID_ARG, __FUNCTION__);
> +        goto error;
> +    }
> +
> +    if (conn->driver->nodeGetCPUStats) {
> +        int ret;
> +        ret = conn->driver->nodeGetCPUStats (conn, cpuNum, params, nparams, flags);
> +        if (ret < 0)
> +            goto error;
> +        return ret;
> +    }
> +    virLibConnError(VIR_ERR_NO_SUPPORT, __FUNCTION__);
> +
> +error:
> +    virDispatchError(conn);
> +    return -1;
> +}
> +
> +/**
>   * virNodeGetFreeMemory:
>   * @conn: pointer to the hypervisor connection
>   *

ACK if the comment is changed.

Daniel
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