Thanks for the proposal! Just a few questions inline, otherwise looks good for my use cases. Philippe Berthault wrote:
Here the new virtual cpu functions proposal. What do you think about it ?
/** * *virVcpuInfo*: structure for information about a virtual CPU in a domain. */ typedef enum { VIR_VCPU_OFFLINE = 0, /* the virtual CPU is offline */ VIR_VCPU_RUNNING = 1, /* the virtual CPU is running */ VIR_VCPU_BLOCKED = 2, /* the virtual CPU is blocked on resource */ *} virVcpuState*;
typedef struct _virVcpuInfo virVcpuInfo; struct _virVcpuInfo { unsigned int number; /* virtual CPU number */ int state; /* value from virVcpuState */ unsigned long long cpuTime; /* CPU time used, in nanoseconds */ int cpu; /* real CPU number, or -1 if offline */ }; typedef virVcpuInfo **virVcpuInfoPtr*;
/** * *virDomainSetVcpus*: * @*domain*: pointer to domain object, or NULL for Domain0 * @*nvcpus*: the new number of virtual CPUs for this domain * * Dynamically change the number of virtual CPUs used by the domain. * Note that this call may fail if the underlying virtualization hypervisor * does not support it or if growing the number is arbitrary limited. * This function requires priviledged access to the hypervisor. * * Returns 0 in case of success, -1 in case of failure. */ int *virDomainSetVcpus* (virDomainPtr domain, unsigned int nvcpus);
/** * *virDomainPinVcpu*: * @*domain*: pointer to domain object, or NULL for Domain0 * @*vcpu*: virtual CPU number * @*cpumap*: pointer to a bit map of real CPUs (in 8-bit bytes). * Each bit set to 1 means that corresponding CPU is usable. * Bytes are stored in little-endian order: CPU0-7, 8-15... * In each byte, lowest CPU number is least significant bit. * @*maplen*: number of bytes in cpumap, from 1 up to size of CPU map in * underlying virtualization system (Xen...). * If maplen < size, missing bytes are set to zero. * If maplen > size, failure code is returned. * * Dynamically change the real CPUs which can be allocated to a virtual CPU. * This function requires priviledged access to the hypervisor. * * Returns 0 in case of success, -1 in case of failure. */ int *virDomainPinVcpu* (virDomainPtr domain, unsigned int vcpu, unsigned char *cpumap, int maplen);
How do I get the "size of CPU map in underlying virtualization system" described in maplen comments?
/* Macros for bit manipulation in cpumap */ #define *USE_CPU*(cpumap,cpu) (cpumap[(cpu)/8] |= (1<<((cpu)%8))) #define *UNUSE_CPU*(cpumap,cpu) (cpumap[(cpu)/8] &= ~(1<<((cpu)%8)))
/** * *virDomainGetVcpus*: * @*domain*: pointer to domain object, or NULL for Domain0 * @*info*: pointer to an array of virVcpuInfo structures * @*maxinfo*: number of structures in info array * @*cpumaps*: pointer to a bit map of real CPUs for all vcpus of this domain. * If cpumaps is NULL, then no cpumap information is returned by the API. * It's assumed there is <maxinfo> cpumap in cpumaps. * The memory allocated to cpumaps must be (maxinfo * maplen) bytes. * One cpumap inside cupmaps have the format described in virDomainPinVcpu API. * @*maplen*: number of bytes in one cpumap, from 1 up to size of CPU map in * underlying virtualization system (Xen...). * * Extract information about virtual CPUs of domain, store it in info array. * * Returns the number of info filled in case of success, -1 in case of failure. */ int *virDomainGetVcpus* (virDomainPtr domain, virVcpuInfoPtr info, int maxinfo, unsigned char *cpumaps, /* may be NULL */ int maplen);
If there is no physical cpu affinity (e.g. the default - vcpus can float among any pcpu), does each cpumap in cpumaps have all bits set? Do we indicate no affinity by having all possible pcpus marked as bound?
/* Macros for bit testing in cpumaps */ #define *CPU_USABLE*(cpumaps,maplen,vcpu,cpu) \ (cpumaps[((vcpu)*(maplen))+((cpu)/8)] & (1<<((cpu)%8)))
/* * Macro for copying the cpumap of a vcpu from cupmaps inside a standalone cpumap. * This macro is useful in case of using virDomainPinVcpu() after virDomainGetVcpus(). * cpumap must be previously allocated. */ #define *COPY_CPUMAP*(cpumaps,maplen,vcpu,cpumap) \ memcpy(cpumap, &(cpumaps[(vcpu)*(maplen)]), (maplen))
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