#!/usr/bin/awk -f
# Script to analyze experimental results of our branch prediction heuristics
-# Contributed by Jan Hubicka, SuSE inc.
-# Copyright (C) 2001 Free Software Foundation, Inc.
+# Contributed by Jan Hubicka, SuSE Inc.
+# Copyright (C) 2001, 2003 Free Software Foundation, Inc.
#
-# This file is part of GNU CC.
+# This file is part of GCC.
#
-# GNU CC is free software; you can redistribute it and/or modify
+# GCC is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
+# the Free Software Foundation; either version 3, or (at your option)
# any later version.
#
-# GNU CC is distributed in the hope that it will be useful,
+# GCC is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
-# along with GNU CC; see the file COPYING. If not, write to
-# the Free Software Foundation, 59 Temple Place - Suite 330,
-# Boston, MA 02111-1307, USA.
+# along with GCC; see the file COPYING. If not, write to
+# the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+# Boston, MA 02110-1301, USA.
#
#
# This script is used to calculate two basic properties of the branch prediction
-# heuristics - coverage and hitrate. Coverage is number of executions of given
+# heuristics - coverage and hitrate. Coverage is number of executions of a given
# branch matched by the heuristics and hitrate is probability that once branch is
# predicted as taken it is really taken.
#
-# These values are usefull to determine quality of given heuristics and hitrate
+# These values are useful to determine the quality of given heuristics. Hitrate
# may be directly used in predict.c.
#
# Usage:
-# step 1: compile and profile your program. You need to use -fprofile-arcs
+# Step 1: Compile and profile your program. You need to use -fprofile-arcs
# flag to get the profiles
-# step 2: Generate log files. The information about given heuristics are
-# saved into *.life dumps. You need to pass -df swtich to compiler as well
-# as -fbranch-probabilities to get results of profiling noted in the dumps.
-# Ensure that there is no "Arc profiling: some edge counts were bad." warnings.
-# Keep the -fprofile-arcs switch to ensure that CFGs match.
-# step 3: Run this script to concatetation of all *.life files:
+# Step 2: Generate log files. The information about given heuristics are
+# saved into *.bp dumps. You need to pass the -db switch to the compiler as well
+# as -fbranch-probabilities to get the results of profiling noted in the dumps.
+# Ensure that there are no "Arc profiling: some edge counts were bad." warnings.
+# Step 3: Run this script to concatenate all *.life files:
# analyze_brprob `find . -name *.life`
# the information is collected and print once all files are parsed. This
# may take a while.
-# Note that script does use bc to perform long arithmetic.
-# step 4: Read the results. Basically following table is printed:
-# (this is just example from very early stages of branch prediction pass
+# Note that the script does use bc to perform long arithmetic.
+# Step 4: Read the results. Basically the following table is printed:
+# (this is just an example from a very early stage of branch prediction pass
# development, so please don't take these numbers seriously)
#
#HEURISTICS BRANCHES (REL) HITRATE COVERAGE (REL)
#loop branch 51 1.5% 99.26%/ 99.27% 26854 0.3%
#noreturn call 951 27.6% 100.00%/100.00% 1759809 17.6%
#
-# The heuristics called "first match" is heuristics used by gcc branch
+# The heuristic called "first match" is a heuristic used by GCC branch
# prediction pass and it predicts 89.92% branches correctly.
#
# The quality of heuristics can be rated using both, coverage and hitrate
# parameters. For example "loop branch" heuristics (predicting loopback edge
-# as taken) have both very high hitrate and coverage, so it is very usefull.
+# as taken) have both very high hitrate and coverage, so it is very useful.
# On the other hand, "exit block" heuristics (predicting exit edges as not
-# taken) have good hitrate, but poor coverage, so only 3 branches has been
-# predicted. The "loop header" heuristics have problem, since it tends to
+# taken) have good hitrate, but poor coverage, so only 3 branches have been
+# predicted. The "loop header" heuristic has problems, since it tends to
# misspredict.
#
# The implementation of this script is somewhat brute force. My awk skills
if (int(pred) < 50.0)
{
- hit = count - hit;
+ hit = count"-"hit;
}
counts[name]=counts[name] "+" count
hits[name]=hits[name] "+" hit
- if (int (hit) < (int (count) / 2))
- hit = count - hit;
- phits[name]=phits[name] "+" hit
+ phits[name]=phits[name] "+(("hit")<"count"/2)*("count"-("hit"))+(("hit")>="count"/2)*("hit")"
#BC crashes on long strings. Irritating.
- if (length(counts[name]) > 4000)
- {
- counts[name] = longeval (counts[name])
- hits[name] = longeval (hits[name])
- phits[name] = longeval (phits[name])
- }
+ if (length(counts[name]) > 2000)
+ counts[name] = longeval(counts[name])
+ if (length(hits[name]) > 2000)
+ hits[name] = longeval(hits[name])
+ if (length(phits[name]) > 2000)
+ phits[name] = longeval(phits[name])
}
END {
# Heuristics called combined predicts just everything.
- maxcounts = longeval (counts["first match"])
- maxbranches = branches["first match"]
- max = names["firat match"]
- printf("HEURISTICS BRANCHES (REL) HITRATE COVERAGE (REL)\n")
+ maxcounts = longeval(counts["combined"])
+ maxbranches = branches["combined"]
+ max = names["combined"]
+ printf("HEURISTICS BRANCHES (REL) HITRATE COVERAGE (REL)\n")
for (i = 0; i < nnames ; i++)
{
name = names[i]
- counts[name] = longeval (counts[name])
- printf ("%-27s %8i %5.1f%% %6s%%/%6s%% %12s %5.1f%%\n",
+ counts[name] = longeval(counts[name])
+ printf ("%-26s %8i %5.1f%% %6s%% / %6s%% %12s %5.1f%%\n",
name,
branches[name], branches[name] * 100 / maxbranches,
- longeval ("("hits[name]") * 100 /(" counts[name]"-0.00001)"),
- longeval ("("phits[name]") * 100 /(" counts[name]"-0.00001)"),
- counts[name], longeval (counts[name]" * 100 / ("maxcounts"-0.00001)"))
+ longeval("("hits[name]") * 100 /(" counts[name]"-0.00001)"),
+ longeval("("phits[name]") * 100 /(" counts[name]"-0.00001)"),
+ counts[name], longeval(counts[name]" * 100 / ("maxcounts"-0.00001)"))
}
}
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