Re: [RFC PATCH] Add support for RAPL MSRs in KVM/Qemu

["Anthony Harivel" <aharivel@redhat.com>]

Marcelo Tosatti, May 19, 2023 at 20:28:

Hi Marcelo,

> > > > +    /* Assuming those values are the same accross physical system/packages */
> > > > +    maxcpus = get_maxcpus(0); /* Number of CPUS per packages */
> > > > +    maxpkgs = numa_max_node(); /* Number of Packages on the system */
>
> numa_max_node() returns the highest node number available on the current system. 
> (See the node numbers in /sys/devices/system/node/ ). Also see numa_num_configured_nodes().
>
> One can find package topology information from
> /sys/devices/system/cpu/cpuX/topology/
>

Good point. 
I will find a better solution to identify the topology using your hint. 

 > > > +        /* Allocate memory for each thread stats */
> > > > +        thd_stat = (thread_stat *) calloc(num_threads, sizeof(thread_stat));
>
> Can you keep this pre-allocated ? And all other data as well.

Ok no problem.

 > > > +        /* Retrieve all packages power plane energy counter */
> > > > +        for (int i = 0; i <= maxpkgs; i++) {
> > > > +            for (int j = 0; j < num_threads; j++) {
> > > > +                /*
> > > > +                 * Use the first thread we found that ran on the CPU
> > > > +                 * of the package to read the packages energy counter
> > > > +                 */
> > > > +                if (thd_stat[j].numa_node_id == i) {
> > > > +                    pkg_stat[i].e_start = read_msr(MSR_PKG_ENERGY_STATUS, i);
> > > > +                    break;
> > > > +                }
> > > > +            }
> > > > +        }
>
> NUMA node does not map necessarily to one package.

True. I will update this part at the same time with the topology info
discussed above. 

>
> > > > +        /* Sleep a short period while the other threads are working */
> > > > +        usleep(MSR_ENERGY_THREAD_SLEEP_US);
> > > > +
> > > > +        /*
> > > > +         * Retrieve all packages power plane energy counter
> > > > +         * Calculate the delta of all packages
> > > > +         */
> > > > +        for (int i = 0; i <= maxpkgs; i++) {
> > > > +            for (int j = 0; j < num_threads; j++) {
> > > > +                /*
> > > > +                 * Use the first thread we found that ran on the CPU
> > > > +                 * of the package to read the packages energy counter
> > > > +                 */
> > > > +                if (thd_stat[j].numa_node_id == i) {
> > > > +                    pkg_stat[i].e_end =
> > > > +                        read_msr(MSR_PKG_ENERGY_STATUS, thd_stat[j].cpu_id);
>
> This is excessive (to read the MSRs of each package in the system).
>
> Consider 100 Linux guests all of them with this enabled, on a system with
> 4 packages. How many times you'll be reading MSR of each package?

The problem here is that you can have vCPUs that are running on different
packages. However the energy counter of the different packages are
increasing independently. 
Either we "force" somehow users to run only on the same package, either I'm
afraid we are obliged to read all the packages energy counter (when they
are involved in the VM).

Imagine this:

|----pkg-0----|----pkg-1----|
|0|1|2|3|4|5|6|0|1|2|3|4|5|6|
|       |       |       |
| vm-0  |  vm-1 |  vm-2 |

Only vm-1 that has cores from pkg-0 and pkg-1 would have to read both
pkg energy. vm-0 would only read pkg-0 and vm-2 only pkg-1.


>
> Moreover, don't want to readmsr on an isolated CPU.
>

Could you explain me why ?

 > 
> > No problem, let me try to explain: 
> > a QEMU process is composed of vCPU thread(s) and non-vCPU thread(s) (IO,
> > emulated device,...). Each of those threads can run on different cores
> > that can belongs to the same Package or not.
> > The MSR_PKG_ENERGY_STATUS is a counter that increment for the whole
> > Package domain. If you read this MSR from any core that belongs to the 
> > package, you will retrieve the same number.
> > So when I need to read the MSR, I only need to read once for all the
> > threads that are running on cores of each Package.
>
> T=0	read p1v0 (== MSR_PKG_ENERGY_STATUS)
> T=1	vcpu-1 executing in core1
> 	vcpu-2 executing in core2
> 	vcpu-3 executing in core2
> T=2	read p1v1
>
> Won't you be exposing (p1v1-p1v0)/3 by 3 in this case, to the 
> virtual MSR_PKG_ENERGY_STATUS?
>

No, because if we take for exemple a 4 cores per package with 100 ticks per second,
the maximum number of ticks for all the cores in this packages would be
400 ticks per second. 
So if 2 or more vcpus are sharing the same core, they will be maxout by the
100 ticks per second anyway and so ratio will still be ok. 


> > Now let's talk about the implementation of the emulated value. 
> > I've created a thread that does in an infinite loop the following:
> > - Retrieve all the QEMU threads + statistics about them 
> > - Read the energy counter of each Package involved 
> > - Sleep for 1sec (1sec is arbitrary)
> > - Calculate the delta of ticks for each threads so that we know how much
> >   time each threads has been scheduled during the Sleep period
>
> Intel docs mention the counter can overflow (faster with higher 
> energy consumption). Are you handling the overflow case?
>

Should we ? On baremetal, anyone reading the MSRs should handle the
overflow case, I guess on a guest this should be the same.
But I'll make sure *not* to output negative energy value for sure!

> > - Read again the energy counter of each Package involved and calculate
> >   the delta of the counter so that we know how much the counter has
> >   increased during the Sleep period
> > - Calculate the ratio for each vCPU thread and deduct the energy spent
> >   for each vCPU
> > - Calculate the amount of energy spent for all non-vCPU and evenly
> >   spread it to the vCPU
> > - Update each virtual MSR for each vCPU
> > 
> > Obviously, this is working better and more consistently with vCPU pinning 
> > and proper isolation of the cores in the package. 
>
> Do you really need to measure the consumption for QEMU threads? I'd say
> only measuring for the vcpus is sufficient.
>

What if a process in the guest is actually doing a lot of IO ?
The QEMU workers managing those IO would be consumming, no ?
But if this is unsignicant I can remove it.

> > So those virtual MSRs are updated roughly each second (could be changed
> > by updating MSR_ENERGY_THREAD_SLEEP_US). Compared to the real MSRs which 
> > are updated by the microcode every 1ms.
>
> How useful are the measurements for the guest, then? (I mean, doesnt a
> 1 second interval render the measurements less useful).
>

We can always reduce the sleeping time. 
I guess we can also set it with a parameter like:
-accel kvm,rapl=true,update-period=500

with update-period, the interval in milliseconds between updates. 

> > Concerning the "real" power consumption, we have to not forget that the
> > RAPL interface energy data is not the result of a physical measurement. 
> > It is a set of architectural events from each core, processor
> > graphic, IO, etc. and combines them with energy weights to predict the
> > package's active power consumption.
> > 
> > IMO it is not really important because the idea behind this patch is to
> > give estimated values to the guests so that software running inside
> > VM can make use of power tools which are all reading those MSRs (or the
> > RAPL driver sys interface) to retrieve power consumption.
>
> Can you describe some use-cases... Because what seems to be useful
> (actually, what seem to be possible) is for users to measure the 
> energy consumption of a package. 
>

Yes and here they will do the same. Except that for the moment I don't
have any solution to overcome the fact that each vcpu will have his own
package. 
When a software will read MSR_PKG_ENERGY_STATUS of pkg-0, it will also
read the energy of the vcpu-0 because we are in single vcpu per virtual
socket.
I would say it might give better granularity of the power consumption:
If a process in guest is running only on one isolated vcpu, reading the
package MSR of this vcpu would theorically gives the consumption of this
process directly. Whereas in baremetal, we need to take the other cores
of the package into account.

> So if you think, OK i can read the energy consumption information
> from within a guest, but i know its the energy consumption divided
> by the amount of time the qemu threads executed, how useful that
> measure is ?

It gives what the guest has actually consume and inside the guest there
are processes that are running.
There are many tools [1][2][3] that use thoses MSRs for metrics to calculate
the power consumption of applications/processes in order to optimize
their code. 

What I'm trying to achieve here is enabling this possibilities inside VM. 

>
> Why not expose the actual delta from the MSRs, rather than diving
> by amount of time the qemu threads execute.
>

Imagine 2 identical VMs on the same package: 
VM-1 is hogging cores and VM-2 is doing nothing. 
If we only report delta of the MSRs, both VM would consume the same
which is wrong. 
This is why I'm doing ratio of the energy depending on the QEMU threads. 
because a vCPU is just a thread and the /proc/<pid>/stat can give us 
the amount of time spend by each thread on the cores.  

Thanks a lot for your input,

Anthony



[1]: https://github.com/sustainable-computing-io/kepler
[2]: https://powerapi.org/
[3]: https://github.com/hubblo-org/scaphandre



> > > > +
> > > > +        /* Delta of ticks spend by each thread between the sample */
> > > > +        for (int i = 0; i < num_threads; i++) {
> > > > +            if (read_thread_stat(&thd_stat[i], pid, 1) != 0) {
> > > > +                /*
> > > > +                 * We don't count the dead thread
> > > > +                 * i.e threads that existed before the sleep
> > > > +                 * and not anymore
> > > > +                 */
> > > > +                thd_stat[i].delta_ticks = 0;
> > > > +            } else {
> > > > +                delta_ticks(thd_stat, i);
> > > > +            }
> > > > +        }
> > > > +
> > > > +        /*
> > > > +         * Identify the vCPU threads
> > > > +         * Calculate the Number of vCPU per package
> > > > +         */
> > > > +        CPU_FOREACH(cpu) {
> > > > +            for (int i = 0; i < num_threads; i++) {
> > > > +                if (cpu->thread_id == thd_stat[i].thread_id) {
> > > > +                    thd_stat[i].is_vcpu = true;
> > > > +                    thd_stat[i].vcpu_id = cpu->cpu_index;
> > > > +                    pkg_stat[thd_stat[i].numa_node_id].nb_vcpu++;
> > > > +                    break;
> > > > +                }
> > > > +            }
> > > > +        }
> > > > +
> > > > +        /* Calculate the total energy of all non-vCPU thread */
> > > > +        for (int i = 0; i < num_threads; i++) {
> > > > +            double temp;
> > > > +            if ((thd_stat[i].is_vcpu != true) &&
> > > > +                (thd_stat[i].delta_ticks > 0)) {
> > > > +                temp = get_ratio(pkg_stat, thd_stat, maxticks, i);
> > > > +                pkg_stat[thd_stat[i].numa_node_id].e_ratio
> > > > +                    += (uint64_t)lround(temp);
> > > > +            }
> > > > +        }
> > > > +
> > > > +        /* Calculate the ratio per non-vCPU thread of each package */
> > > > +        for (int i = 0; i <= maxpkgs; i++) {
> > > > +            if (pkg_stat[i].nb_vcpu > 0) {
> > > > +                pkg_stat[i].e_ratio = pkg_stat[i].e_ratio / pkg_stat[i].nb_vcpu;
> > > > +            }
> > > > +        }
> > > > +
> > > > +        /* Calculate the energy for each vCPU thread */
> > > > +        for (int i = 0; i < num_threads; i++) {
> > > > +            double temp;
> > > > +
> > > > +            if ((thd_stat[i].is_vcpu == true) &&
> > > > +                (thd_stat[i].delta_ticks > 0)) {
> > > > +                temp = get_ratio(pkg_stat, thd_stat, maxticks, i);
> > > > +                vmsr->msr_value[thd_stat[i].vcpu_id] += (uint64_t)lround(temp);
> > > > +                vmsr->msr_value[thd_stat[i].vcpu_id] \
> > > > +                    += pkg_stat[thd_stat[i].numa_node_id].e_ratio;
> > > > +            }
> > > > +        }
> > > > +
> > > > +        /* free all memory */
> > > > +        for (int i = 0; i < num_threads; i++) {
> > > > +            free(thd_stat[i].utime);
> > > > +            free(thd_stat[i].stime);
> > > > +        }
> > > > +        free(thd_stat);
> > > > +        free(thread_ids);
> > > > +    }
> > > > +
> > > > +    rcu_unregister_thread();
> > > > +    return NULL;
> > > > +}
> > > > +
> > > > +static int kvm_msr_energy_thread_init(KVMState *s, MachineState *ms)
> > > > +{
> > > > +    struct KVMMsrEnergy *r = &s->msr_energy;
> > > > +
> > > > +    /* Retrieve the number of vCPU */
> > > > +    r->cpus = ms->smp.cpus;
> > > > +
> > > > +    /* Allocate register memory (MSR_PKG_STATUS) for each vCPU */
> > > > +    r->msr_value = calloc(r->cpus, sizeof(r->msr_value));
> > > > +
> > > > +    qemu_thread_create(&r->msr_thr, "kvm-msr",
> > > > +                       kvm_msr_energy_thread,
> > > > +                       s, QEMU_THREAD_JOINABLE);
> > > > +
> > > > +    return 0;
> > > > +}
> > > > +
> > > >  int kvm_arch_init(MachineState *ms, KVMState *s)
> > > >  {
> > > >      uint64_t identity_base = 0xfffbc000;
> > > > @@ -2765,6 +2998,46 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
> > > >                           strerror(-ret));
> > > >              exit(1);
> > > >          }
> > > > +
> > > > +        if (s->msr_energy.enable == true) {
> > > > +
> > > > +            r = kvm_filter_msr(s, MSR_RAPL_POWER_UNIT,
> > > > +                               kvm_rdmsr_rapl_power_unit, NULL);
> > > > +            if (!r) {
> > > > +                error_report("Could not install MSR_RAPL_POWER_UNIT \
> > > > +                                handler: %s",
> > > > +                             strerror(-ret));
> > > > +                exit(1);
> > > > +            }
> > > > +
> > > > +            r = kvm_filter_msr(s, MSR_PKG_POWER_LIMIT,
> > > > +                               kvm_rdmsr_pkg_power_limit, NULL);
> > > > +            if (!r) {
> > > > +                error_report("Could not install MSR_PKG_POWER_LIMIT \
> > > > +                                handler: %s",
> > > > +                             strerror(-ret));
> > > > +                exit(1);
> > > > +            }
> > > > +
> > > > +            r = kvm_filter_msr(s, MSR_PKG_POWER_INFO,
> > > > +                               kvm_rdmsr_pkg_power_info, NULL);
> > > > +            if (!r) {
> > > > +                error_report("Could not install MSR_PKG_POWER_INFO \
> > > > +                                handler: %s",
> > > > +                             strerror(-ret));
> > > > +                exit(1);
> > > > +            }
> > > > +            r = kvm_filter_msr(s, MSR_PKG_ENERGY_STATUS,
> > > > +                               kvm_rdmsr_pkg_energy_status, NULL);
> > > > +            if (!r) {
> > > > +                error_report("Could not install MSR_PKG_ENERGY_STATUS \
> > > > +                                handler: %s",
> > > > +                             strerror(-ret));
> > > > +                exit(1);
> > > > +            } else {
> > > > +                kvm_msr_energy_thread_init(s, ms);
> > > > +            }
> > > > +        }
> > > >      }
> > > >  
> > > >      return 0;
> > > > diff --git a/target/i386/kvm/meson.build b/target/i386/kvm/meson.build
> > > > index 322272091bce..9cdc93c6c439 100644
> > > > --- a/target/i386/kvm/meson.build
> > > > +++ b/target/i386/kvm/meson.build
> > > > @@ -5,6 +5,7 @@ i386_softmmu_kvm_ss = ss.source_set()
> > > >  i386_softmmu_kvm_ss.add(files(
> > > >    'kvm.c',
> > > >    'kvm-cpu.c',
> > > > +  'vmsr_energy.c',
> > > >  ))
> > > >  
> > > >  i386_softmmu_kvm_ss.add(when: 'CONFIG_XEN_EMU', if_true: files('xen-emu.c'))
> > > > diff --git a/target/i386/kvm/vmsr_energy.c b/target/i386/kvm/vmsr_energy.c
> > > > new file mode 100644
> > > > index 000000000000..8bd86b32becf
> > > > --- /dev/null
> > > > +++ b/target/i386/kvm/vmsr_energy.c
> > > > @@ -0,0 +1,132 @@
> > > > +/*
> > > > + * QEMU KVM support -- x86 virtual energy-related MSR.
> > > > + *
> > > > + * Copyright 2023 Red Hat, Inc. 2023
> > > > + *
> > > > + *  Author:
> > > > + *      Anthony Harivel <aharivel@redhat.com>
> > > > + *
> > > > + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> > > > + * See the COPYING file in the top-level directory.
> > > > + *
> > > > + */
> > > > +
> > > > +#include "vmsr_energy.h"
> > > > +
> > > > +#define MAX_PATH_LEN 50
> > > > +#define MAX_LINE_LEN 500
> > > > +
> > > > +uint64_t read_msr(uint32_t reg, unsigned int cpu_id)
> > > > +{
> > > > +    int fd;
> > > > +    uint64_t data;
> > > > +
> > > > +    char path[MAX_PATH_LEN];
> > > > +    snprintf(path, MAX_PATH_LEN, "/dev/cpu/%u/msr", cpu_id);
> > > > +
> > > > +    fd = open(path , O_RDONLY);
> > > > +    if (fd < 0) {
> > > > +        return 0;
> > > > +    }
> > > > +    if (pread(fd, &data, sizeof data, reg) != sizeof data) {
> > > > +        data = 0;
> > > > +    }
> > > > +
> > > > +    close(fd);
> > > > +    return data;
> > > > +}
> > > > +
> > > > +/* Retrieve the number of physical CPU on the package */
> > > > +unsigned int get_maxcpus(unsigned int package_num)
> > > > +{
> > > > +    int k, ncpus;
> > > > +    unsigned int maxcpus;
> > > > +    struct bitmask *cpus;
> > > > +
> > > > +    cpus = numa_allocate_cpumask();
> > > > +    ncpus = cpus->size;
> > > > +
> > > > +    if (numa_node_to_cpus(package_num, cpus) < 0) {
> > > > +        printf("node %u failed to convert\n", package_num);
> > > > +    }
> > > > +
> > > > +    maxcpus = 0;
> > > > +    for (k = 0; k < ncpus; k++) {
> > > > +        if (numa_bitmask_isbitset(cpus, k)) {
> > > > +            maxcpus++;
> > > > +        }
> > > > +    }
> > > > +
> > > > +    return maxcpus;
> > > > +}
> > > > +
> > > > +int read_thread_stat(struct thread_stat *thread, int pid, int index)
> > > > +{
> > > > +    char path[MAX_PATH_LEN];
> > > > +    snprintf(path, MAX_PATH_LEN, "/proc/%u/task/%d/stat", pid, \
> > > > +             thread->thread_id);
> > > > +
> > > > +    FILE *file = fopen(path, "r");
> > > > +    if (file == NULL) {
> > > > +        return -1;
> > > > +    }
> > > > +
> > > > +    if (fscanf(file, "%*d (%*[^)]) %*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u"
> > > > +        " %llu %llu %*d %*d %*d %*d %*d %*d %*u %*u %*d %*u %*u"
> > > > +        " %*u %*u %*u %*u %*u %*u %*u %*u %*u %*d %*u %*u %u",
> > > > +           &thread->utime[index], &thread->stime[index], &thread->cpu_id) != 3)
> > > > +        return -1;
> > > > +
> > > > +    fclose(file);
> > > > +    return 0;
> > > > +}
> > > > +
> > > > +/* Read QEMU stat task folder to retrieve all QEMU threads ID */
> > > > +pid_t *get_thread_ids(pid_t pid, int *num_threads)
> > > > +{
> > > > +    char path[100];
> > > > +    sprintf(path, "/proc/%d/task", pid);
> > > > +
> > > > +    DIR *dir = opendir(path);
> > > > +    if (dir == NULL) {
> > > > +        perror("opendir");
> > > > +        return NULL;
> > > > +    }
> > > > +
> > > > +    pid_t *thread_ids = NULL;
> > > > +    int thread_count = 0;
> > > > +
> > > > +    struct dirent *ent;
> > > > +    while ((ent = readdir(dir)) != NULL) {
> > > > +        if (ent->d_name[0] == '.') {
> > > > +            continue;
> > > > +        }
> > > > +        pid_t tid = atoi(ent->d_name);
> > > > +        if (pid != tid) {
> > > > +            thread_ids = realloc(thread_ids,
> > > > +                                 (thread_count + 1) * sizeof(pid_t));
> > > > +            thread_ids[thread_count] = tid;
> > > > +            thread_count++;
> > > > +        }
> > > > +    }
> > > > +
> > > > +    closedir(dir);
> > > > +
> > > > +    *num_threads = thread_count;
> > > > +    return thread_ids;
> > > > +}
> > > > +
> > > > +void delta_ticks(thread_stat *thd_stat, int i)
> > > > +{
> > > > +    thd_stat[i].delta_ticks = (thd_stat[i].utime[1] + thd_stat[i].stime[1])
> > > > +                            - (thd_stat[i].utime[0] + thd_stat[i].stime[0]);
> > > > +}
> > > > +
> > > > +double get_ratio(package_energy_stat *pkg_stat,
> > > > +                        thread_stat *thd_stat,
> > > > +                        int maxticks, int i) {
> > > > +
> > > > +    return (pkg_stat[thd_stat[i].numa_node_id].e_delta / 100.0)
> > > > +            * ((100.0 / maxticks) * thd_stat[i].delta_ticks);
> > > > +}
> > > > +
> > > > diff --git a/target/i386/kvm/vmsr_energy.h b/target/i386/kvm/vmsr_energy.h
> > > > new file mode 100644
> > > > index 000000000000..5f79d2cbe00d
> > > > --- /dev/null
> > > > +++ b/target/i386/kvm/vmsr_energy.h
> > > > @@ -0,0 +1,80 @@
> > > > +/*
> > > > + * QEMU KVM support -- x86 virtual energy-related MSR.
> > > > + *
> > > > + * Copyright 2023 Red Hat, Inc. 2023
> > > > + *
> > > > + *  Author:
> > > > + *      Anthony Harivel <aharivel@redhat.com>
> > > > + *
> > > > + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> > > > + * See the COPYING file in the top-level directory.
> > > > + *
> > > > + */
> > > > +
> > > > +#ifndef VMSR_ENERGY_H
> > > > +#define VMSR_ENERGY_H
> > > > +
> > > > +#include "qemu/osdep.h"
> > > > +
> > > > +#include <numa.h>
> > > > +
> > > > +/*
> > > > + * Define the interval time in micro seconds between 2 samples of
> > > > + * energy related MSRs
> > > > + */
> > > > +#define MSR_ENERGY_THREAD_SLEEP_US 1000000.0
> > > > +
> > > > +/*
> > > > + * Thread statistic
> > > > + * @ thread_id: TID (thread ID)
> > > > + * @ is_vcpu: true is thread is vCPU thread
> > > > + * @ cpu_id: CPU number last executed on
> > > > + * @ vcpu_id: vCPU ID
> > > > + * @ numa_node_id:node number of the CPU
> > > > + * @ utime: amount of clock ticks the thread
> > > > + *          has been scheduled in User mode
> > > > + * @ stime: amount of clock ticks the thread
> > > > + *          has been scheduled in System mode
> > > > + * @ delta_ticks: delta of utime+stime between
> > > > + *          the two samples (before/after sleep)
> > > > + */
> > > > +struct thread_stat {
> > > > +    unsigned int thread_id;
> > > > +    bool is_vcpu;
> > > > +    unsigned int cpu_id;
> > > > +    unsigned int vcpu_id;
> > > > +    unsigned int numa_node_id;
> > > > +    unsigned long long *utime;
> > > > +    unsigned long long *stime;
> > > > +    unsigned long long delta_ticks;
> > > > +};
> > > > +
> > > > +/*
> > > > + * Package statistic
> > > > + * @ e_start: package energy counter before the sleep
> > > > + * @ e_end: package energy counter after the sleep
> > > > + * @ e_delta: delta of package energy counter
> > > > + * @ e_ratio: store the energy ratio of non-vCPU thread
> > > > + * @ nb_vcpu: number of vCPU running on this package
> > > > + */
> > > > +struct packge_energy_stat {
> > > > +    uint64_t e_start;
> > > > +    uint64_t e_end;
> > > > +    uint64_t e_delta;
> > > > +    uint64_t e_ratio;
> > > > +    unsigned int nb_vcpu;
> > > > +};
> > > > +
> > > > +typedef struct thread_stat thread_stat;
> > > > +typedef struct packge_energy_stat package_energy_stat;
> > > > +
> > > > +uint64_t read_msr(uint32_t reg, unsigned int cpu_id);
> > > > +void delta_ticks(thread_stat *thd_stat, int i);
> > > > +unsigned int get_maxcpus(unsigned int package_num);
> > > > +int read_thread_stat(struct thread_stat *thread, int pid, int index);
> > > > +pid_t *get_thread_ids(pid_t pid, int *num_threads);
> > > > +double get_ratio(package_energy_stat *pkg_stat,
> > > > +                        thread_stat *thd_stat,
> > > > +                        int maxticks, int i);
> > > > +
> > > > +#endif /* VMSR_ENERGY_H */
> > > > -- 
> > > > 2.40.1
> > > > 
> > > > 
> > 
> >