bcc/tools: Add cpu filter (-c CPU) for softirqs & hardirqs

4 files changed, 58 insertions, 10 deletions

diff --git a/man/man8/hardirqs.8 b/man/man8/hardirqs.8
index 12ae6be5..aa9afb84 100644
--- a/man/man8/hardirqs.8
+++ b/man/man8/hardirqs.8
@@ -33,6 +33,9 @@ Count events only.
 .TP
 \-d
 Show IRQ time distribution as histograms.
+.TP
+\-c CPU
+Trace on this CPU only.
 .SH EXAMPLES
 .TP
 Sum hard IRQ event time until Ctrl-C:
@@ -50,6 +53,10 @@ Print 1 second summaries, 10 times:
 1 second summaries, printed in nanoseconds, with timestamps:
 #
 .B hardirqs \-NT 1
+.TP
+Sum hard IRQ event time on CPU 1 until Ctrl-C:
+#
+.B hardirqs \-c 1
 .SH FIELDS
 .TP
 HARDIRQ
@@ -91,6 +98,6 @@ Linux
 .SH STABILITY
 Unstable - in development.
 .SH AUTHOR
-Brendan Gregg, Hengqi Chen
+Brendan Gregg, Hengqi Chen, Rocky Xing
 .SH SEE ALSO
 softirqs(8)
diff --git a/man/man8/softirqs.8 b/man/man8/softirqs.8
index a9a14414..408c5a02 100644
--- a/man/man8/softirqs.8
+++ b/man/man8/softirqs.8
@@ -30,6 +30,9 @@ Output in nanoseconds
 .TP
 \-d
 Show IRQ time distribution as histograms
+.TP
+\-c CPU
+Trace on this CPU only.
 .SH EXAMPLES
 .TP
 Sum soft IRQ event time until Ctrl-C:
@@ -47,6 +50,10 @@ Print 1 second summaries, 10 times:
 1 second summaries, printed in nanoseconds, with timestamps:
 #
 .B softirqs \-NT 1
+.TP
+Sum soft IRQ event time on CPU 1 until Ctrl-C:
+#
+.B softirqs \-c 1
 .SH FIELDS
 .TP
 SOFTIRQ
@@ -88,6 +95,6 @@ Linux
 .SH STABILITY
 Unstable - in development.
 .SH AUTHORS
-Brendan Gregg, Sasha Goldshtein
+Brendan Gregg, Sasha Goldshtein, Rocky Xing
 .SH SEE ALSO
 hardirqs(8)
diff --git a/tools/hardirqs.py b/tools/hardirqs.py
index 0eeddddc..4e373d9c 100755
--- a/tools/hardirqs.py
+++ b/tools/hardirqs.py
@@ -4,7 +4,7 @@
 # hardirqs  Summarize hard IRQ (interrupt) event time.
 #           For Linux, uses BCC, eBPF.
 #
-# USAGE: hardirqs [-h] [-T] [-N] [-C] [-d] [interval] [outputs]
+# USAGE: hardirqs [-h] [-T] [-N] [-C] [-d] [-c CPU] [interval] [outputs]
 #
 # Thanks Amer Ather for help understanding irq behavior.
 #
@@ -13,6 +13,7 @@
 #
 # 19-Oct-2015   Brendan Gregg   Created this.
 # 22-May-2021   Hengqi Chen     Migrated to kernel tracepoints.
+# 07-Mar-2022   Rocky Xing      Added CPU filter support.
 
 from __future__ import print_function
 from bcc import BPF
@@ -25,6 +26,7 @@ examples = """examples:
     ./hardirqs -d         # show hard irq event time as histograms
     ./hardirqs 1 10       # print 1 second summaries, 10 times
     ./hardirqs -NT 1      # 1s summaries, nanoseconds, and timestamps
+    ./hardirqs -c 1       # sum hard irq event time on CPU 1 only
 """
 parser = argparse.ArgumentParser(
     description="Summarize hard irq event time as histograms",
@@ -38,6 +40,8 @@ parser.add_argument("-C", "--count", action="store_true",
     help="show event counts instead of timing")
 parser.add_argument("-d", "--dist", action="store_true",
     help="show distributions as histograms")
+parser.add_argument("-c", "--cpu", type=int,
+    help="trace this CPU only")
 parser.add_argument("interval", nargs="?", default=99999999,
     help="output interval, in seconds")
 parser.add_argument("outputs", nargs="?", default=99999999,
@@ -94,9 +98,12 @@ TRACEPOINT_PROBE(irq, irq_handler_entry)
 {
     struct entry_key key = {};
     irq_name_t name = {};
+    u32 cpu = bpf_get_smp_processor_id();
+
+    FILTER_CPU
 
     key.tid = bpf_get_current_pid_tgid();
-    key.cpu_id = bpf_get_smp_processor_id();
+    key.cpu_id = cpu;
 
     TP_DATA_LOC_READ_STR(&name.name, name, sizeof(name));
     irqnames.update(&key, &name);
@@ -106,9 +113,12 @@ TRACEPOINT_PROBE(irq, irq_handler_entry)
 TRACEPOINT_PROBE(irq, irq_handler_exit)
 {
     struct entry_key key = {};
+    u32 cpu = bpf_get_smp_processor_id();
+
+    FILTER_CPU
 
     key.tid = bpf_get_current_pid_tgid();
-    key.cpu_id = bpf_get_smp_processor_id();
+    key.cpu_id = cpu;
 
     // check ret value of irq handler is not IRQ_NONE to make sure
     // the current event belong to this irq handler
@@ -137,9 +147,12 @@ TRACEPOINT_PROBE(irq, irq_handler_entry)
     u64 ts = bpf_ktime_get_ns();
     irq_name_t name = {};
     struct entry_key key = {};
+    u32 cpu = bpf_get_smp_processor_id();
+
+    FILTER_CPU
 
     key.tid = bpf_get_current_pid_tgid();
-    key.cpu_id = bpf_get_smp_processor_id();
+    key.cpu_id = cpu;
 
     TP_DATA_LOC_READ_STR(&name.name, name, sizeof(name));
     irqnames.update(&key, &name);
@@ -152,9 +165,10 @@ TRACEPOINT_PROBE(irq, irq_handler_exit)
     u64 *tsp, delta;
     irq_name_t *namep;
     struct entry_key key = {};
+    u32 cpu = bpf_get_smp_processor_id();
 
     key.tid = bpf_get_current_pid_tgid();
-    key.cpu_id = bpf_get_smp_processor_id();
+    key.cpu_id = cpu;
 
     // check ret value of irq handler is not IRQ_NONE to make sure
     // the current event belong to this irq handler
@@ -195,6 +209,11 @@ else:
         'irq_key_t key = {.slot = 0 /* ignore */};' +
         'bpf_probe_read_kernel(&key.name, sizeof(key.name), name);' +
         'dist.atomic_increment(key, delta);')
+if args.cpu is not None:
+    bpf_text = bpf_text.replace('FILTER_CPU',
+        'if (cpu != %d) { return 0; }' % int(args.cpu))
+else:
+    bpf_text = bpf_text.replace('FILTER_CPU', '')
 if debug or args.ebpf:
     print(bpf_text)
     if args.ebpf:
diff --git a/tools/softirqs.py b/tools/softirqs.py
index ba0dac36..3d4f8d27 100755
--- a/tools/softirqs.py
+++ b/tools/softirqs.py
@@ -4,13 +4,14 @@
 # softirqs  Summarize soft IRQ (interrupt) event time.
 #           For Linux, uses BCC, eBPF.
 #
-# USAGE: softirqs [-h] [-T] [-N] [-d] [interval] [count]
+# USAGE: softirqs [-h] [-T] [-N] [-d] [-c CPU] [interval] [count]
 #
 # Copyright (c) 2015 Brendan Gregg.
 # Licensed under the Apache License, Version 2.0 (the "License")
 #
 # 20-Oct-2015   Brendan Gregg     Created this.
 # 03-Apr-2017   Sasha Goldshtein  Migrated to kernel tracepoints.
+# 07-Mar-2022   Rocky Xing        Added CPU filter support.
 
 from __future__ import print_function
 from bcc import BPF
@@ -23,6 +24,7 @@ examples = """examples:
     ./softirqs -d         # show soft irq event time as histograms
     ./softirqs 1 10       # print 1 second summaries, 10 times
     ./softirqs -NT 1      # 1s summaries, nanoseconds, and timestamps
+    ./softirqs -c 1       # sum soft irq event time on CPU 1 only
 """
 parser = argparse.ArgumentParser(
     description="Summarize soft irq event time as histograms.",
@@ -34,6 +36,8 @@ parser.add_argument("-N", "--nanoseconds", action="store_true",
     help="output in nanoseconds")
 parser.add_argument("-d", "--dist", action="store_true",
     help="show distributions as histograms")
+parser.add_argument("-c", "--cpu", type=int,
+    help="trace this CPU only")
 parser.add_argument("interval", nargs="?", default=99999999,
     help="output interval, in seconds")
 parser.add_argument("count", nargs="?", default=99999999,
@@ -77,9 +81,12 @@ TRACEPOINT_PROBE(irq, softirq_entry)
 {
     account_val_t val = {};
     entry_key_t key = {};
+    u32 cpu = bpf_get_smp_processor_id();
+
+    FILTER_CPU
 
     key.pid = bpf_get_current_pid_tgid();
-    key.cpu = bpf_get_smp_processor_id();
+    key.cpu = cpu;
     val.ts = bpf_ktime_get_ns();
     val.vec = args->vec;
 
@@ -95,9 +102,12 @@ TRACEPOINT_PROBE(irq, softirq_exit)
     account_val_t *valp;
     irq_key_t key = {0};
     entry_key_t entry_key = {};
+    u32 cpu = bpf_get_smp_processor_id();
+
+    FILTER_CPU
 
     entry_key.pid = bpf_get_current_pid_tgid();
-    entry_key.cpu = bpf_get_smp_processor_id();
+    entry_key.cpu = cpu;
 
     // fetch timestamp and calculate delta
     valp = start.lookup(&entry_key);
@@ -124,6 +134,11 @@ else:
     bpf_text = bpf_text.replace('STORE',
         'key.vec = valp->vec; ' +
         'dist.atomic_increment(key, delta);')
+if args.cpu is not None:
+    bpf_text = bpf_text.replace('FILTER_CPU',
+        'if (cpu != %d) { return 0; }' % int(args.cpu))
+else:
+    bpf_text = bpf_text.replace('FILTER_CPU', '')
 if debug or args.ebpf:
     print(bpf_text)
     if args.ebpf: