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authorTonghao Zhang <tong@infragraf.org>2023-02-02 16:17:01 +0300
committerMartin KaFai Lau <martin.lau@kernel.org>2023-02-03 09:20:14 +0300
commit377c16fa3f3c60d21e4b05314c8be034ce37f2eb (patch)
tree874ac0e7fdbbdb7d79b54c103caf147371389428 /tools/bpf
parent0a312cf8dbec111df6d5c72e0a6b017d48a829c6 (diff)
downloadlinux-377c16fa3f3c60d21e4b05314c8be034ce37f2eb.tar.xz
bpftool: profile online CPUs instead of possible
The number of online cpu may be not equal to possible cpu. "bpftool prog profile" can not create pmu event on possible but on online cpu. $ dmidecode -s system-product-name PowerEdge R620 $ cat /sys/devices/system/cpu/possible 0-47 $ cat /sys/devices/system/cpu/online 0-31 Disable cpu dynamically: $ echo 0 > /sys/devices/system/cpu/cpuX/online If one cpu is offline, perf_event_open will return ENODEV. To fix this issue: * check value returned and skip offline cpu. * close pmu_fd immediately on error path, avoid fd leaking. Fixes: 47c09d6a9f67 ("bpftool: Introduce "prog profile" command") Signed-off-by: Tonghao Zhang <tong@infragraf.org> Cc: Quentin Monnet <quentin@isovalent.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <martin.lau@linux.dev> Cc: Song Liu <song@kernel.org> Cc: Yonghong Song <yhs@fb.com> Cc: John Fastabend <john.fastabend@gmail.com> Cc: KP Singh <kpsingh@kernel.org> Cc: Stanislav Fomichev <sdf@google.com> Cc: Hao Luo <haoluo@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/r/20230202131701.29519-1-tong@infragraf.org Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Diffstat (limited to 'tools/bpf')
-rw-r--r--tools/bpf/bpftool/prog.c38
1 files changed, 30 insertions, 8 deletions
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index cfc9fdc1e863..e87738dbffc1 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -2233,10 +2233,38 @@ static void profile_close_perf_events(struct profiler_bpf *obj)
profile_perf_event_cnt = 0;
}
+static int profile_open_perf_event(int mid, int cpu, int map_fd)
+{
+ int pmu_fd;
+
+ pmu_fd = syscall(__NR_perf_event_open, &metrics[mid].attr,
+ -1 /*pid*/, cpu, -1 /*group_fd*/, 0);
+ if (pmu_fd < 0) {
+ if (errno == ENODEV) {
+ p_info("cpu %d may be offline, skip %s profiling.",
+ cpu, metrics[mid].name);
+ profile_perf_event_cnt++;
+ return 0;
+ }
+ return -1;
+ }
+
+ if (bpf_map_update_elem(map_fd,
+ &profile_perf_event_cnt,
+ &pmu_fd, BPF_ANY) ||
+ ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0)) {
+ close(pmu_fd);
+ return -1;
+ }
+
+ profile_perf_events[profile_perf_event_cnt++] = pmu_fd;
+ return 0;
+}
+
static int profile_open_perf_events(struct profiler_bpf *obj)
{
unsigned int cpu, m;
- int map_fd, pmu_fd;
+ int map_fd;
profile_perf_events = calloc(
sizeof(int), obj->rodata->num_cpu * obj->rodata->num_metric);
@@ -2255,17 +2283,11 @@ static int profile_open_perf_events(struct profiler_bpf *obj)
if (!metrics[m].selected)
continue;
for (cpu = 0; cpu < obj->rodata->num_cpu; cpu++) {
- pmu_fd = syscall(__NR_perf_event_open, &metrics[m].attr,
- -1/*pid*/, cpu, -1/*group_fd*/, 0);
- if (pmu_fd < 0 ||
- bpf_map_update_elem(map_fd, &profile_perf_event_cnt,
- &pmu_fd, BPF_ANY) ||
- ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0)) {
+ if (profile_open_perf_event(m, cpu, map_fd)) {
p_err("failed to create event %s on cpu %d",
metrics[m].name, cpu);
return -1;
}
- profile_perf_events[profile_perf_event_cnt++] = pmu_fd;
}
}
return 0;