From 0ce58bae851dc3728af1c0b83905cd6b4565417a Mon Sep 17 00:00:00 2001
From: Ben Hutchings <ben@decadent.org.uk>
Date: Mon, 20 May 2013 14:45:42 +0000
Subject: [PATCH] perf: net_dropmonitor: Use bisection in symbol lookup
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
tools/perf/scripts/python/net_dropmonitor.py | 22 ++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)
diff --git a/tools/perf/scripts/python/net_dropmonitor.py b/tools/perf/scripts/python/net_dropmonitor.py
index 6acdc82ef47f..32fcee05c0f6 100755
--- a/tools/perf/scripts/python/net_dropmonitor.py
+++ b/tools/perf/scripts/python/net_dropmonitor.py
@@ -40,10 +40,24 @@ def get_kallsyms_table():
def get_sym(sloc):
loc = int(sloc)
- for symloc, name in kallsyms[::-1]:
- if loc >= symloc:
- return (name, loc - symloc)
- return (None, 0)
+
+ # Invariant: kallsyms[i][0] <= loc for all 0 <= i <= start
+ # kallsyms[i][0] > loc for all end <= i < len(kallsyms)
+ start, end = -1, len(kallsyms)
+ while end != start + 1:
+ pivot = (start + end) // 2
+ if loc < kallsyms[pivot][0]:
+ end = pivot
+ else:
+ start = pivot
+
+ # Now (start == -1 or kallsyms[start][0] <= loc)
+ # and (start == len(kallsyms) - 1 or loc < kallsyms[start + 1][0])
+ if start >= 0:
+ symloc, name = kallsyms[start]
+ return (name, loc - symloc)
+ else:
+ return (None, 0)
def print_drop_table():
print "%25s %25s %25s" % ("LOCATION", "OFFSET", "COUNT")
--
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