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* [PATCH 2/2] scripts/bloat-o-meter: compile .NUMBER regex
@ 2016-11-19  0:44 Alexey Dobriyan
  0 siblings, 0 replies; only message in thread
From: Alexey Dobriyan @ 2016-11-19  0:44 UTC (permalink / raw)
  To: akpm; +Cc: linux-kernel, mpm

Every often used regex is better be compiled in Python.

Speedup is about ~9.8% (whee!)

	$ perf stat -r 16 taskset -c 15 ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux >/dev/null
	7.091202853 seconds time elapsed                                          ( +-  0.15% )

	+re.compile
	6.397564973 seconds time elapsed                                          ( +-  0.34% )

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 scripts/bloat-o-meter |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/scripts/bloat-o-meter
+++ b/scripts/bloat-o-meter
@@ -16,6 +16,8 @@ if len(sys.argv) != 3:
     sys.stderr.write("usage: %s file1 file2\n" % sys.argv[0])
     sys.exit(-1)
 
+re_NUMBER = re.compile(r'\.[0-9]+')
+
 def getsizes(file):
     sym = {}
     with os.popen("nm --size-sort " + file) as f:
@@ -28,7 +30,7 @@ def getsizes(file):
                 if name.startswith("compat_SyS_"): continue
                 if name == "linux_banner": continue
                 # statics and some other optimizations adds random .NUMBER
-                name = re.sub(r'\.[0-9]+', '', name)
+                name = re_NUMBER.sub('', name)
                 sym[name] = sym.get(name, 0) + int(size, 16)
     return sym
 

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