perf jevents: Drop or simplify small integer values

Prior to this patch '0' would be dropped as the config values default
to 0. Some json values are hex and the string '0' wouldn't match '0x0'
as zero. Add a more robust is_zero test to drop these event terms.

When encoding numbers as hex, if the number is between 0 and 9
inclusive then don't add a 0x prefix.

Update test expectations for these changes.

On x86 this reduces the event/metric C string by 58,411 bytes.

Signed-off-by: Ian Rogers <[e-mail]>
Reviewed-by: Kan Liang <[e-mail]>
Cc: Edward Baker <[e-mail]>
Cc: Perry Taylor <[e-mail]>
Cc: Weilin Wang <[e-mail]>
Cc: John Garry <[e-mail]>
Cc: Jing Zhang <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: Michael Petlan <[e-mail]>
Cc: Veronika Molnarova <[e-mail]>
Signed-off-by: Namhyung Kim <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

tools/perf/pmu-events/jevents.py

···
 
     def llx(x: int) -> str:
       """Convert an int to a string similar to a printf modifier of %#llx."""
-      return '0' if x == 0 else hex(x)
+      return str(x) if x >= 0 and x < 10 else hex(x)
 
     def fixdesc(s: str) -> str:
       """Fix formatting issue for the desc string."""
···
       }
       return table[unit] if unit in table else f'uncore_{unit.lower()}'
 
+    def is_zero(val: str) -> bool:
+        try:
+            if val.startswith('0x'):
+                return int(val, 16) == 0
+            else:
+                return int(val) == 0
+        except e:
+            return False
+
+    def canonicalize_value(val: str) -> str:
+        try:
+            if val.startswith('0x'):
+                return llx(int(val, 16))
+            return str(int(val))
+        except e:
+            return val
+
     eventcode = 0
     if 'EventCode' in jd:
       eventcode = int(jd['EventCode'].split(',', 1)[0], 0)
···
         ('RdWrMask', 'rdwrmask='),
     ]
     for key, value in event_fields:
-      if key in jd and jd[key] != '0':
-        event += ',' + value + jd[key]
+      if key in jd and not is_zero(jd[key]):
+        event += f',{value}{canonicalize_value(jd[key])}'
     if filter:
       event += f',{filter}'
     if msr:

tools/perf/tests/pmu-events.c

···
 	.event = {
 		.pmu = "default_core",
 		.name = "segment_reg_loads.any",
-		.event = "event=0x6,period=200000,umask=0x80",
+		.event = "event=6,period=200000,umask=0x80",
 		.desc = "Number of segment register loads",
 		.topic = "other",
 	},
···
 	.event = {
 		.pmu = "default_core",
 		.name = "dispatch_blocked.any",
-		.event = "event=0x9,period=200000,umask=0x20",
+		.event = "event=9,period=200000,umask=0x20",
 		.desc = "Memory cluster signals to block micro-op dispatch for any reason",
 		.topic = "other",
 	},
···
 	.event = {
 		.pmu = "default_core",
 		.name = "eist_trans",
-		.event = "event=0x3a,period=200000,umask=0x0",
+		.event = "event=0x3a,period=200000",
 		.desc = "Number of Enhanced Intel SpeedStep(R) Technology (EIST) transitions",
 		.topic = "other",
 	},
-	.alias_str = "event=0x3a,period=0x30d40,umask=0",
+	.alias_str = "event=0x3a,period=0x30d40",
 	.alias_long_desc = "Number of Enhanced Intel SpeedStep(R) Technology (EIST) transitions",
 };
 
···
 static const struct perf_pmu_test_event uncore_hisi_ddrc_flux_wcmd = {
 	.event = {
 		.name = "uncore_hisi_ddrc.flux_wcmd",
-		.event = "event=0x2",
+		.event = "event=2",
 		.desc = "DDRC write commands",
 		.topic = "uncore",
 		.long_desc = "DDRC write commands",
···
 static const struct perf_pmu_test_event uncore_hyphen = {
 	.event = {
 		.name = "event-hyphen",
-		.event = "event=0xe0,umask=0x00",
+		.event = "event=0xe0",
 		.desc = "UNC_CBO_HYPHEN",
 		.topic = "uncore",
 		.long_desc = "UNC_CBO_HYPHEN",
 		.pmu = "uncore_cbox",
 	},
-	.alias_str = "event=0xe0,umask=0",
+	.alias_str = "event=0xe0",
 	.alias_long_desc = "UNC_CBO_HYPHEN",
 	.matching_pmu = "uncore_cbox_0",
 };
···
 static const struct perf_pmu_test_event uncore_two_hyph = {
 	.event = {
 		.name = "event-two-hyph",
-		.event = "event=0xc0,umask=0x00",
+		.event = "event=0xc0",
 		.desc = "UNC_CBO_TWO_HYPH",
 		.topic = "uncore",
 		.long_desc = "UNC_CBO_TWO_HYPH",
 		.pmu = "uncore_cbox",
 	},
-	.alias_str = "event=0xc0,umask=0",
+	.alias_str = "event=0xc0",
 	.alias_long_desc = "UNC_CBO_TWO_HYPH",
 	.matching_pmu = "uncore_cbox_0",
 };
···
 static const struct perf_pmu_test_event uncore_hisi_l3c_rd_hit_cpipe = {
 	.event = {
 		.name = "uncore_hisi_l3c.rd_hit_cpipe",
-		.event = "event=0x7",
+		.event = "event=7",
 		.desc = "Total read hits",
 		.topic = "uncore",
 		.long_desc = "Total read hits",
···
 static const struct perf_pmu_test_event sys_cmn_pmu_hnf_cache_miss = {
 	.event = {
 		.name = "sys_cmn_pmu.hnf_cache_miss",
-		.event = "eventid=0x1,type=0x5",
+		.event = "eventid=1,type=5",
 		.desc = "Counts total cache misses in first lookup result (high priority)",
 		.topic = "uncore",
 		.pmu = "uncore_sys_cmn_pmu",