aboutsummaryrefslogtreecommitdiffstats
path: root/lib/Target/X86/X86SchedHaswell.td
diff options
context:
space:
mode:
authorAndrew Trick <atrick@apple.com>2013-04-13 06:07:43 +0000
committerAndrew Trick <atrick@apple.com>2013-04-13 06:07:43 +0000
commitf521997303553846685409630fca2b46758b6eac (patch)
tree1fbc9f8d5e0224b397908f9890f5d04bcc682564 /lib/Target/X86/X86SchedHaswell.td
parent4392f0f407fe4e2a9ec53b2560a1cbf86357c190 (diff)
downloadexternal_llvm-f521997303553846685409630fca2b46758b6eac.zip
external_llvm-f521997303553846685409630fca2b46758b6eac.tar.gz
external_llvm-f521997303553846685409630fca2b46758b6eac.tar.bz2
X86 machine model: reduce SandyBridge and Haswell ILPWindow.
The initial values were arbitrary. I want them to be more conservative. This represents the number of latency cycles hidden by OOO execution. In practice, I think it should be within a small factor of the complex floating point operation latency so the scheduler can make some attempt to hide latency even for smallish blocks. These are by no means the best values, just a starting point for tuning heuristics. Some benchmarks such as TSVC run faster with this lower value for SandyBridge. I haven't run anything on Haswell, but it's shouldn't be 2x SB. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179450 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/X86/X86SchedHaswell.td')
-rw-r--r--lib/Target/X86/X86SchedHaswell.td2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/Target/X86/X86SchedHaswell.td b/lib/Target/X86/X86SchedHaswell.td
index 7de6791..84c9203 100644
--- a/lib/Target/X86/X86SchedHaswell.td
+++ b/lib/Target/X86/X86SchedHaswell.td
@@ -18,7 +18,7 @@ def HaswellModel : SchedMachineModel {
let IssueWidth = 4;
let MinLatency = 0; // 0 = Out-of-order execution.
let LoadLatency = 4;
- let ILPWindow = 40;
+ let ILPWindow = 30;
let MispredictPenalty = 16;
}