From 8cb7a188ac33b71ec24a9081d1521f46dcab53c4 Mon Sep 17 00:00:00 2001 From: Athira Rajeev Date: Tue, 12 Apr 2022 22:10:58 +0530 Subject: perf bench: Fix numa testcase to check if CPU used to bind task is online Perf numa bench test fails with error: Testcase: ./perf bench numa mem -p 2 -t 1 -P 1024 -C 0,8 -M 1,0 -s 20 -zZq --thp 1 --no-data_rand_walk Failure snippet: <<>> Running 'numa/mem' benchmark: # Running main, "perf bench numa numa-mem -p 2 -t 1 -P 1024 -C 0,8 -M 1,0 -s 20 -zZq --thp 1 --no-data_rand_walk" perf: bench/numa.c:333: bind_to_cpumask: Assertion `!(ret)' failed. <<>> The Testcases uses CPU's 0 and 8. In function "parse_setup_cpu_list", There is check to see if cpu number is greater than max cpu's possible in the system ie via "if (bind_cpu_0 >= g->p.nr_cpus || bind_cpu_1 >= g->p.nr_cpus) {". But it could happen that system has say 48 CPU's, but only number of online CPU's is 0-7. Other CPU's are offlined. Since "g->p.nr_cpus" is 48, so function will go ahead and set bit for CPU 8 also in cpumask ( td->bind_cpumask). bind_to_cpumask function is called to set affinity using sched_setaffinity and the cpumask. Since the CPU8 is not present, set affinity will fail here with EINVAL. Fix this issue by adding a check to make sure that, CPU's provided in the input argument values are online before proceeding further and skip the test. For this, include new helper function "is_cpu_online" in "tools/perf/util/header.c". Since "BIT(x)" definition will get included from header.h, remove that from bench/numa.c Reported-by: Disha Goel Signed-off-by: Athira Jajeev Tested-by: Disha Goel Cc: Ian Rogers Cc: Jiri Olsa Cc: Kajol Jain Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Nageswara R Sastry Cc: Srikar Dronamraju Cc: linuxppc-dev@lists.ozlabs.org Link: https://lore.kernel.org/r/20220412164059.42654-2-atrajeev@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/bench/numa.c | 8 ++++++-- tools/perf/util/header.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++ tools/perf/util/header.h | 1 + 3 files changed, 58 insertions(+), 2 deletions(-) (limited to 'tools/perf') diff --git a/tools/perf/bench/numa.c b/tools/perf/bench/numa.c index f2640179ada9..c838c248aa2c 100644 --- a/tools/perf/bench/numa.c +++ b/tools/perf/bench/numa.c @@ -34,6 +34,7 @@ #include #include +#include "../util/header.h" #include #include @@ -585,6 +586,11 @@ static int parse_setup_cpu_list(void) return -1; } + if (is_cpu_online(bind_cpu_0) != 1 || is_cpu_online(bind_cpu_1) != 1) { + printf("\nTest not applicable, bind_cpu_0 or bind_cpu_1 is offline\n"); + return -1; + } + BUG_ON(bind_cpu_0 < 0 || bind_cpu_1 < 0); BUG_ON(bind_cpu_0 > bind_cpu_1); @@ -752,8 +758,6 @@ static int parse_nodes_opt(const struct option *opt __maybe_unused, return parse_node_list(arg); } -#define BIT(x) (1ul << x) - static inline uint32_t lfsr_32(uint32_t lfsr) { const uint32_t taps = BIT(1) | BIT(5) | BIT(6) | BIT(31); diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index d546ff724dbe..a27132e5a5ef 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -983,6 +983,57 @@ static int write_dir_format(struct feat_fd *ff, return do_write(ff, &data->dir.version, sizeof(data->dir.version)); } +/* + * Check whether a CPU is online + * + * Returns: + * 1 -> if CPU is online + * 0 -> if CPU is offline + * -1 -> error case + */ +int is_cpu_online(unsigned int cpu) +{ + char *str; + size_t strlen; + char buf[256]; + int status = -1; + struct stat statbuf; + + snprintf(buf, sizeof(buf), + "/sys/devices/system/cpu/cpu%d", cpu); + if (stat(buf, &statbuf) != 0) + return 0; + + /* + * Check if /sys/devices/system/cpu/cpux/online file + * exists. Some cases cpu0 won't have online file since + * it is not expected to be turned off generally. + * In kernels without CONFIG_HOTPLUG_CPU, this + * file won't exist + */ + snprintf(buf, sizeof(buf), + "/sys/devices/system/cpu/cpu%d/online", cpu); + if (stat(buf, &statbuf) != 0) + return 1; + + /* + * Read online file using sysfs__read_str. + * If read or open fails, return -1. + * If read succeeds, return value from file + * which gets stored in "str" + */ + snprintf(buf, sizeof(buf), + "devices/system/cpu/cpu%d/online", cpu); + + if (sysfs__read_str(buf, &str, &strlen) < 0) + return status; + + status = atoi(str); + + free(str); + return status; +} + #ifdef HAVE_LIBBPF_SUPPORT static int write_bpf_prog_info(struct feat_fd *ff, struct evlist *evlist __maybe_unused) diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h index c9e3265832d9..0eb4bc29a5a4 100644 --- a/tools/perf/util/header.h +++ b/tools/perf/util/header.h @@ -158,6 +158,7 @@ int do_write(struct feat_fd *fd, const void *buf, size_t size); int write_padded(struct feat_fd *fd, const void *bf, size_t count, size_t count_aligned); +int is_cpu_online(unsigned int cpu); /* * arch specific callback */ -- cgit v1.2.3