[PATCH v2] perf scripts: Add configurable sorting option to powerpc-hcalls

[Shivani Nittor <shivani@linux.ibm.com>]

The powerpc-hcalls.py script currently prints hypercall
statistics in a fixed sort order based on the number of
hcall occurrences, making it difficult to analyze hcalls
from different execution characteristics.

Add support for runtime-configurable sorting so users
can order hypercall statistics by count, minimum
latency, maximum latency, or average latency using
a --sort option.

Parse arguments through sys.argv to support perf script
argument passing semantics.

Example:

perf record -a -e powerpc* sleep 10

perf script -s ./powerpc-hcalls.py -i ./perf.data -- --sort=max

SORT KEY = max
hcall                            count   min(ns)   max(ns)   avg(ns)

H_SEND_LOGICAL_LAN                  47      7380     40148      8739
H_VIO_SIGNAL                       706       880     17454      1911
H_RANDOM                             1     15176     15176     15176
H_PUT_TCE_INDIRECT                   4      3032     10444      4956
H_ADD_LOGICAL_LAN_BUFFER           363      1250      8716      1534
H_SEND_CRQ                           8      2086      6846      3044
H_PUT_TCE                            9      1284      4932      2646
H_STUFF_TCE                         13      1620      3962      2358

This makes it easier to identify frequently occurring
or high-latency hypercalls depending on the analysis
being performed.

Signed-off-by: Shivani Nittor <shivani@linux.ibm.com>
---
Changelog:
v1 -> v2
- Add bounds check for --sort argument handling
- Prevent IndexError when sort key is omitted

---
tools/perf/scripts/python/powerpc-hcalls.py | 38 ++++++++++++++++++++-
1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/tools/perf/scripts/python/powerpc-hcalls.py b/tools/perf/scripts/python/powerpc-hcalls.py
index 8b78dc790adb..e5b0c1bee65f 100644
--- a/tools/perf/scripts/python/powerpc-hcalls.py
+++ b/tools/perf/scripts/python/powerpc-hcalls.py
@@ -25,6 +25,7 @@ from Util import *
 #	} ...
 # }
 output = {}
+sort_key = 'count'
 
 # d_enter: {
 #	cpu: {
@@ -158,10 +159,45 @@ def hcall_table_lookup(opcode):
 
 print_ptrn = '%-28s%10s%10s%10s%10s'
 
+def sort_output(opcode):
+	stats = output[opcode]
+
+	if sort_key == 'min':
+		return stats['min']
+	if sort_key == 'max':
+		return stats['max']
+	if sort_key == 'avg':
+		return stats['time'] // stats['cnt']
+
+	return stats['cnt']
+
+def trace_begin():
+    global sort_key
+
+    i = 1
+    while i < len(sys.argv):
+        arg = sys.argv[i]
+
+        if arg == '-s' or arg == '--sort':
+            if i + 1 >= len(sys.argv):
+                print("Error: -s/--sort requires a sort key argument")
+                sys.exit(1)
+            sort_key = sys.argv[i + 1]
+            i += 2
+            continue
+
+        if arg.startswith('--sort='):
+            sort_key = arg.split('=', 1)[1]
+
+        i += 1
+
+    print("SORT KEY =", sort_key)
+
 def trace_end():
 	print(print_ptrn % ('hcall', 'count', 'min(ns)', 'max(ns)', 'avg(ns)'))
 	print('-' * 68)
-	for opcode in output:
+	for opcode in sorted(output, key = sort_output,
+                            reverse=True):
 		h_name = hcall_table_lookup(opcode)
 		time = output[opcode]['time']
 		cnt = output[opcode]['cnt']
-- 
2.54.0