diff options
author | Thomas Renninger <trenn@suse.de> | 2011-08-12 01:11:37 +0200 |
---|---|---|
committer | Dominik Brodowski <linux@dominikbrodowski.net> | 2011-08-15 20:03:10 +0200 |
commit | 7c74d2bc5a9d43d33d6f16c1e706147162e2bc52 (patch) | |
tree | f9a3578dca29ca782df483d9cdc8f5bc376d5ef2 /tools | |
parent | 88f984e0e235f82a5d34f4a99244eeb14e1413e0 (diff) | |
download | lwn-7c74d2bc5a9d43d33d6f16c1e706147162e2bc52.tar.gz lwn-7c74d2bc5a9d43d33d6f16c1e706147162e2bc52.zip |
cpupower: Better detect offlined CPUs
Before, checking for offlined CPUs was done dirty and
it was checked whether topology parsing returned -1 values.
But this is a valid case on a Xen (and possibly other) kernels.
Do proper online/offline checking, also take CONFIG_HOTPLUG_CPU
option into account (no /sys/devices/../cpuX/online file).
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Diffstat (limited to 'tools')
-rw-r--r-- | tools/power/cpupower/utils/helpers/helpers.h | 3 | ||||
-rw-r--r-- | tools/power/cpupower/utils/helpers/sysfs.c | 50 | ||||
-rw-r--r-- | tools/power/cpupower/utils/helpers/sysfs.h | 2 | ||||
-rw-r--r-- | tools/power/cpupower/utils/helpers/topology.c | 5 | ||||
-rw-r--r-- | tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c | 10 |
5 files changed, 66 insertions, 4 deletions
diff --git a/tools/power/cpupower/utils/helpers/helpers.h b/tools/power/cpupower/utils/helpers/helpers.h index 592ee362b877..7a83022733b2 100644 --- a/tools/power/cpupower/utils/helpers/helpers.h +++ b/tools/power/cpupower/utils/helpers/helpers.h @@ -96,6 +96,9 @@ struct cpupower_topology { int pkg; int core; int cpu; + + /* flags */ + unsigned int is_online:1; } *core_info; }; diff --git a/tools/power/cpupower/utils/helpers/sysfs.c b/tools/power/cpupower/utils/helpers/sysfs.c index 55e2466674c6..c6343024a611 100644 --- a/tools/power/cpupower/utils/helpers/sysfs.c +++ b/tools/power/cpupower/utils/helpers/sysfs.c @@ -56,6 +56,56 @@ static unsigned int sysfs_write_file(const char *path, return (unsigned int) numwrite; } +/* + * Detect whether a CPU is online + * + * Returns: + * 1 -> if CPU is online + * 0 -> if CPU is offline + * negative errno values in error case + */ +int sysfs_is_cpu_online(unsigned int cpu) +{ + char path[SYSFS_PATH_MAX]; + int fd; + ssize_t numread; + unsigned long long value; + char linebuf[MAX_LINE_LEN]; + char *endp; + struct stat statbuf; + + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u", cpu); + + if (stat(path, &statbuf) != 0) + return 0; + + /* + * kernel without CONFIG_HOTPLUG_CPU + * -> cpuX directory exists, but not cpuX/online file + */ + snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/online", cpu); + if (stat(path, &statbuf) != 0) + return 1; + + fd = open(path, O_RDONLY); + if (fd == -1) + return -errno; + + numread = read(fd, linebuf, MAX_LINE_LEN - 1); + if (numread < 1) { + close(fd); + return -EIO; + } + linebuf[numread] = '\0'; + close(fd); + + value = strtoull(linebuf, &endp, 0); + if (value > 1 || value < 0) + return -EINVAL; + + return value; +} + /* CPUidle idlestate specific /sys/devices/system/cpu/cpuX/cpuidle/ access */ /* diff --git a/tools/power/cpupower/utils/helpers/sysfs.h b/tools/power/cpupower/utils/helpers/sysfs.h index f9373e090637..8cb797bbceb0 100644 --- a/tools/power/cpupower/utils/helpers/sysfs.h +++ b/tools/power/cpupower/utils/helpers/sysfs.h @@ -7,6 +7,8 @@ extern unsigned int sysfs_read_file(const char *path, char *buf, size_t buflen); +extern int sysfs_is_cpu_online(unsigned int cpu); + extern unsigned long sysfs_get_idlestate_latency(unsigned int cpu, unsigned int idlestate); extern unsigned long sysfs_get_idlestate_usage(unsigned int cpu, diff --git a/tools/power/cpupower/utils/helpers/topology.c b/tools/power/cpupower/utils/helpers/topology.c index 385ee5c7570c..4eae2c47ba48 100644 --- a/tools/power/cpupower/utils/helpers/topology.c +++ b/tools/power/cpupower/utils/helpers/topology.c @@ -41,6 +41,8 @@ struct cpuid_core_info { unsigned int pkg; unsigned int thread; unsigned int cpu; + /* flags */ + unsigned int is_online:1; }; static int __compare(const void *t1, const void *t2) @@ -78,6 +80,8 @@ int get_cpu_topology(struct cpupower_topology *cpu_top) return -ENOMEM; cpu_top->pkgs = cpu_top->cores = 0; for (cpu = 0; cpu < cpus; cpu++) { + cpu_top->core_info[cpu].cpu = cpu; + cpu_top->core_info[cpu].is_online = sysfs_is_cpu_online(cpu); cpu_top->core_info[cpu].pkg = sysfs_topology_read_file(cpu, "physical_package_id"); if ((int)cpu_top->core_info[cpu].pkg != -1 && @@ -85,7 +89,6 @@ int get_cpu_topology(struct cpupower_topology *cpu_top) cpu_top->pkgs = cpu_top->core_info[cpu].pkg; cpu_top->core_info[cpu].core = sysfs_topology_read_file(cpu, "core_id"); - cpu_top->core_info[cpu].cpu = cpu; } cpu_top->pkgs++; diff --git a/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c b/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c index ba4bf068380d..dd8e1ea6e6f2 100644 --- a/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c +++ b/tools/power/cpupower/utils/idle_monitor/cpupower-monitor.c @@ -190,9 +190,13 @@ void print_results(int topology_depth, int cpu) } } } - /* cpu offline */ - if (cpu_top.core_info[cpu].pkg == -1 || - cpu_top.core_info[cpu].core == -1) { + /* + * The monitor could still provide useful data, for example + * AMD HW counters partly sit in PCI config space. + * It's up to the monitor plug-in to check .is_online, this one + * is just for additional info. + */ + if (!cpu_top.core_info[cpu].is_online) { printf(_(" *is offline\n")); return; } else |