On Fri, Aug 26, 2022 at 11:45:00AM -0700, Vipin Sharma wrote: > Add command line options, -c, to run the vcpus and optionally the main > process on the specific cpus on a host machine. This is useful as it > provides a way to analyze performance based on the vcpus and dirty log > worker locations, like on the different numa nodes or on the same numa > nodes. > > Link: https://lore.kernel.org/lkml/20220801151928.270380-1-vipinsh@xxxxxxxxxx > Signed-off-by: Vipin Sharma <vipinsh@xxxxxxxxxx> > Suggested-by: David Matlack <dmatlack@xxxxxxxxxx> > Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx> > Suggested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > --- > .../selftests/kvm/dirty_log_perf_test.c | 23 ++++++- > .../selftests/kvm/include/perf_test_util.h | 4 ++ > .../selftests/kvm/lib/perf_test_util.c | 62 ++++++++++++++++++- > 3 files changed, 86 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c > index 1346f6b5a9bd..9514b5f28b67 100644 > --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c > +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c > @@ -353,7 +353,7 @@ static void help(char *name) > puts(""); > printf("usage: %s [-h] [-i iterations] [-p offset] [-g] " > "[-m mode] [-n] [-b vcpu bytes] [-v vcpus] [-o] [-s mem type]" > - "[-x memslots]\n", name); > + "[-x memslots] [-c physical cpus to run test on]\n", name); > puts(""); > printf(" -i: specify iteration counts (default: %"PRIu64")\n", > TEST_HOST_LOOP_N); > @@ -383,6 +383,18 @@ static void help(char *name) > backing_src_help("-s"); > printf(" -x: Split the memory region into this number of memslots.\n" > " (default: 1)\n"); > + printf(" -c: Comma separated values of the physical CPUs, which will run\n" > + " the vCPUs, optionally, followed by the main application thread cpu.\n" > + " Number of values must be at least the number of vCPUs.\n" > + " The very next number is used to pin main application thread.\n\n" > + " Example: ./dirty_log_perf_test -v 3 -c 22,23,24,50\n" > + " This means that the vcpu 0 will run on the physical cpu 22,\n" > + " vcpu 1 on the physical cpu 23, vcpu 2 on the physical cpu 24\n" > + " and the main thread will run on cpu 50.\n\n" > + " Example: ./dirty_log_perf_test -v 3 -c 22,23,24\n" > + " Same as the previous example except now main application\n" > + " thread can run on any physical cpu\n\n" > + " (default: No cpu mapping)\n"); > puts(""); > exit(0); > } > @@ -398,6 +410,7 @@ int main(int argc, char *argv[]) > .slots = 1, > }; > int opt; > + const char *pcpu_list = NULL; > > dirty_log_manual_caps = > kvm_check_cap(KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2); > @@ -406,11 +419,14 @@ int main(int argc, char *argv[]) > > guest_modes_append_default(); > > - while ((opt = getopt(argc, argv, "b:ef:ghi:m:nop:s:v:x:")) != -1) { > + while ((opt = getopt(argc, argv, "b:c:ef:ghi:m:nop:s:v:x:")) != -1) { > switch (opt) { > case 'b': > guest_percpu_mem_size = parse_size(optarg); > break; > + case 'c': > + pcpu_list = optarg; > + break; > case 'e': > /* 'e' is for evil. */ > run_vcpus_while_disabling_dirty_logging = true; > @@ -459,6 +475,9 @@ int main(int argc, char *argv[]) > } > } > > + if (pcpu_list) > + perf_test_setup_pinning(pcpu_list, nr_vcpus); > + > TEST_ASSERT(p.iterations >= 2, "The test should have at least two iterations"); > > pr_info("Test iterations: %"PRIu64"\n", p.iterations); > diff --git a/tools/testing/selftests/kvm/include/perf_test_util.h b/tools/testing/selftests/kvm/include/perf_test_util.h > index eaa88df0555a..d02619f153a2 100644 > --- a/tools/testing/selftests/kvm/include/perf_test_util.h > +++ b/tools/testing/selftests/kvm/include/perf_test_util.h > @@ -27,6 +27,8 @@ struct perf_test_vcpu_args { > /* Only used by the host userspace part of the vCPU thread */ > struct kvm_vcpu *vcpu; > int vcpu_idx; > + bool pin_pcpu; > + int pcpu; > }; > > struct perf_test_args { > @@ -60,4 +62,6 @@ void perf_test_guest_code(uint32_t vcpu_id); > uint64_t perf_test_nested_pages(int nr_vcpus); > void perf_test_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu *vcpus[]); > > +int perf_test_setup_pinning(const char *pcpus_string, int nr_vcpus); > + > #endif /* SELFTEST_KVM_PERF_TEST_UTIL_H */ > diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c > index 9618b37c66f7..7a1e8223e7c7 100644 > --- a/tools/testing/selftests/kvm/lib/perf_test_util.c > +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c > @@ -2,7 +2,10 @@ > /* > * Copyright (C) 2020, Google LLC. > */ > +#define _GNU_SOURCE > + > #include <inttypes.h> > +#include <sched.h> > > #include "kvm_util.h" > #include "perf_test_util.h" > @@ -240,9 +243,26 @@ void __weak perf_test_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_v > exit(KSFT_SKIP); > } > > +static void pin_me_to_pcpu(int pcpu) > +{ > + cpu_set_t cpuset; > + int err; > + > + CPU_ZERO(&cpuset); > + CPU_SET(pcpu, &cpuset); > + errno = 0; No need to set errno explicitly here since sched_setaffinity() is defined to set errno if it returns -1. > + err = sched_setaffinity(0, sizeof(cpu_set_t), &cpuset); > + TEST_ASSERT(err == 0, "sched_setaffinity errored out: %d\n", errno); TEST_ASSERT() already prints errno. It would be more useful to print @pcpu to help the user debug the failure. Also, use "()" after function names. > +} > + > static void *vcpu_thread_main(void *data) > { > struct vcpu_thread *vcpu = data; > + int idx = vcpu->vcpu_idx; > + struct perf_test_vcpu_args *vcpu_args = &perf_test_args.vcpu_args[idx]; > + > + if (vcpu_args->pin_pcpu) > + pin_me_to_pcpu(vcpu_args->pcpu); > > WRITE_ONCE(vcpu->running, true); > > @@ -255,7 +275,7 @@ static void *vcpu_thread_main(void *data) > while (!READ_ONCE(all_vcpu_threads_running)) > ; > > - vcpu_thread_fn(&perf_test_args.vcpu_args[vcpu->vcpu_idx]); > + vcpu_thread_fn(vcpu_args); > > return NULL; > } > @@ -292,3 +312,43 @@ void perf_test_join_vcpu_threads(int nr_vcpus) > for (i = 0; i < nr_vcpus; i++) > pthread_join(vcpu_threads[i].thread, NULL); > } > + > +int perf_test_setup_pinning(const char *pcpus_string, int nr_vcpus) > +{ > + char delim[2] = ","; > + char *cpu, *cpu_list; > + int i = 0, pcpu_num; > + > + cpu_list = strdup(pcpus_string); > + TEST_ASSERT(cpu_list, "strdup() allocation failed.\n"); > + > + cpu = strtok(cpu_list, delim); > + > + // 1. Get all pcpus for vcpus > + while (cpu && i < nr_vcpus) { > + pcpu_num = atoi_paranoid(cpu); > + TEST_ASSERT(pcpu_num >= 0, "Invalid cpu number: %d\n", pcpu_num); > + > + perf_test_args.vcpu_args[i].pin_pcpu = true; Since pinning vCPU is all or nothing, this can be a single bool instead of per-vCPUs. /* True if vCPUs are pinned to pCPUs. */ perf_test_args.pin_vcpus /* The pCPU to which this vCPU is pinned. Only valid if pin_vcpus is true. */ perf_test_args.vcpus_args[i].pcpu > + perf_test_args.vcpu_args[i++].pcpu = pcpu_num; > + > + cpu = strtok(NULL, delim); > + } > + > + TEST_ASSERT(i == nr_vcpus, > + "Number of pcpus (%d) not sufficient for the number of vcpus (%d).", > + i, nr_vcpus); > + > + // 2. Check if main worker is provided > + if (cpu) { > + pcpu_num = atoi_paranoid(cpu); > + TEST_ASSERT(pcpu_num >= 0, "Invalid cpu number: %d\n", pcpu_num); nite: Create a helper function for this since it's repeated twice. > + > + pin_me_to_pcpu(pcpu_num); > + > + cpu = strtok(NULL, delim); Delete? > + } > + > + free(cpu_list); > + return i; The return value is unused. Drop it until we have a usecase for it. > +} > -- > 2.37.2.672.g94769d06f0-goog >
