Messages in this thread | | | From | "Wang, Wei W" <> | Subject | RE: [PATCH v6 5/5] KVM: selftests: Allowing running dirty_log_perf_test on specific CPUs | Date | Wed, 26 Oct 2022 02:27:53 +0000 |
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On Saturday, October 22, 2022 5:18 AM, Vipin Sharma wrote: > +static void pin_this_task_to_pcpu(uint32_t pcpu) { > + cpu_set_t mask; > + int r; > + > + CPU_ZERO(&mask); > + CPU_SET(pcpu, &mask); > + r = sched_setaffinity(0, sizeof(mask), &mask); > + TEST_ASSERT(!r, "sched_setaffinity() failed for pCPU '%u'.\n", pcpu); > +} > + > static void *vcpu_thread_main(void *data) { > + struct perf_test_vcpu_args *vcpu_args; > struct vcpu_thread *vcpu = data; > > + vcpu_args = &perf_test_args.vcpu_args[vcpu->vcpu_idx]; > + > + if (perf_test_args.pin_vcpus) > + pin_this_task_to_pcpu(vcpu_args->pcpu); > +
I think it would be better to do the thread pinning at the time when the thread is created by providing a pthread_attr_t attr, e.g. :
pthread_attr_t attr;
CPU_SET(vcpu->pcpu, &cpu_set); pthread_attr_setaffinity_np(&attr, sizeof(cpu_set_t), &cpu_set); pthread_create(thread, attr,...);
Also, pinning a vCPU thread to a pCPU is a general operation which other users would need. I think we could make it more general and put it to kvm_util, e.g. adding it to the helper function that I'm trying to create
+ * Create a vcpu thread with user provided attribute and the name in + * "vcpu-##id" format. + */ +void __vcpu_thread_create(struct kvm_vcpu *vcpu, const pthread_attr_t *attr, + void *(*start_routine)(void *), uint32_t private_data_size)
(https://lore.kernel.org/kvm/20221024113445.1022147-1-wei.w.wang@intel.com/T/#m0ceed820278a9deb199871ee6da7d6ec54d065f4)
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