From: Andrea Di Biagio <Andrea_DiBiagio@sn.scee.net>
Date: Wed, 19 Jun 2019 16:10:58 +0000 (+0000)
Subject: [llvm-mca][docs] clarify how the quality of the perf report is affected by the qualit... 
X-Git-Tag: llvmorg-10-init~2530
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=792510f86949b9c14c2f26843f612e96ffbf82ec;p=platform%2Fupstream%2Fllvm.git

[llvm-mca][docs] clarify how the quality of the perf report is affected by the quality of the scheduling models.

Differential Revision: https://reviews.llvm.org/D63556

llvm-svn: 363830
---

diff --git a/llvm/docs/CommandGuide/llvm-mca.rst b/llvm/docs/CommandGuide/llvm-mca.rst
index d8c3b57..847a043 100644
--- a/llvm/docs/CommandGuide/llvm-mca.rst
+++ b/llvm/docs/CommandGuide/llvm-mca.rst
@@ -38,6 +38,17 @@ Or for Intel syntax:
 
   $ clang foo.c -O2 -target x86_64-unknown-unknown -mllvm -x86-asm-syntax=intel -S -o - | llvm-mca -mcpu=btver2
 
+Scheduling models are not just used to compute instruction latencies and
+throughput, but also to understand what processor resources are available
+and how to simulate them.
+
+By design, the quality of the analysis conducted by :program:`llvm-mca` is
+inevitably affected by the quality of the scheduling models in LLVM.
+
+If you see that the performance report is not accurate for a processor,
+please `file a bug <https://bugs.llvm.org/enter_bug.cgi?product=libraries>`_
+against the appropriate backend.
+
 OPTIONS
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