profile: exclude CPU idle stacks by default (#2166)
profile: exclude CPU idle stacks by default
diff --git a/tools/profile.py b/tools/profile.py
index a803b9e..89cd523 100755
--- a/tools/profile.py
+++ b/tools/profile.py
@@ -9,6 +9,8 @@
# counting there. Only the unique stacks and counts are passed to user space
# at the end of the profile, greatly reducing the kernel<->user transfer.
#
+# By default CPU idle stacks are excluded by simply excluding PID 0.
+#
# REQUIRES: Linux 4.9+ (BPF_PROG_TYPE_PERF_EVENT support). Under tools/old is
# a version of this tool that may work on Linux 4.6 - 4.8.
#
@@ -22,6 +24,7 @@
#
# 15-Jul-2016 Brendan Gregg Created this.
# 20-Oct-2016 " " Switched to use the new 4.9 support.
+# 26-Jan-2019 " " Changed to exclude CPU idle by default.
from __future__ import print_function
from bcc import BPF, PerfType, PerfSWConfig
@@ -93,6 +96,8 @@
help="insert delimiter between kernel/user stacks")
parser.add_argument("-a", "--annotations", action="store_true",
help="add _[k] annotations to kernel frames")
+parser.add_argument("-I", "--include-idle", action="store_true",
+ help="include CPU idle stacks")
parser.add_argument("-f", "--folded", action="store_true",
help="output folded format, one line per stack (for flame graphs)")
parser.add_argument("--stack-storage-size", default=16384,
@@ -141,6 +146,9 @@
int do_perf_event(struct bpf_perf_event_data *ctx) {
u32 pid = bpf_get_current_pid_tgid() >> 32;
+ if (IDLE_FILTER)
+ return 0;
+
if (!(THREAD_FILTER))
return 0;
@@ -184,6 +192,12 @@
}
"""
+# set idle filter
+idle_filter = "pid == 0"
+if args.include_idle:
+ idle_filter = "0"
+bpf_text = bpf_text.replace('IDLE_FILTER', idle_filter)
+
# set thread filter
thread_context = ""
perf_filter = "-a"