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 | 6 ++ .../selftests/kvm/lib/perf_test_util.c | 58 ++++++++++++++++++- 3 files changed, 84 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 ecda802b78ff..33f83e423f75 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; @@ -458,6 +474,9 @@ 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..8197260e3b6b 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; + /* The pCPU to which this vCPU is pinned. Only valid if pin_vcpus is true. */ + int pcpu; }; struct perf_test_args { @@ -39,6 +41,8 @@ struct perf_test_args { /* Run vCPUs in L2 instead of L1, if the architecture supports it. */ bool nested; + /* True if all vCPUs are pinned to pCPUs*/ + bool pin_vcpus; struct perf_test_vcpu_args vcpu_args[KVM_MAX_VCPUS]; }; @@ -60,4 +64,6 @@ 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[]); +void 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..5d1aca0482b4 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 +243,25 @@ 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); + err = sched_setaffinity(0, sizeof(cpu_set_t), &cpuset); + TEST_ASSERT(err == 0, "sched_setaffinity() errored out for pcpu: %d\n", pcpu); +} + 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 (perf_test_args.pin_vcpus) + pin_me_to_pcpu(vcpu_args->pcpu); WRITE_ONCE(vcpu->running, true); @@ -255,7 +274,7 @@ 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 +311,40 @@ void perf_test_join_vcpu_threads(int nr_vcpus) for (i = 0; i < nr_vcpus; i++) pthread_join(vcpu_threads[i].thread, NULL); } + +static int pcpu_num(const char *cpu_str) +{ + int pcpu = atoi_paranoid(cpu_str); + TEST_ASSERT(pcpu >= 0, "Invalid cpu number: %d\n", pcpu); + return pcpu; +} + +void perf_test_setup_pinning(const char *pcpus_string, int nr_vcpus) +{ + char delim[2] = ","; + char *cpu, *cpu_list; + int i = 0; + + 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) { + perf_test_args.vcpu_args[i++].pcpu = pcpu_num(cpu); + cpu = strtok(NULL, delim); + } + + TEST_ASSERT(i == nr_vcpus, + "Number of pcpus (%d) not sufficient for the number of vcpus (%d).", + i, nr_vcpus); + + perf_test_args.pin_vcpus = true; + + // 2. Check if main worker is provided + if (cpu) + pin_me_to_pcpu(pcpu_num(cpu)); + + free(cpu_list); +} -- 2.38.0.rc1.362.ged0d419d3c-goog
