[llvm] r363830 - [llvm-mca][docs] clarify how the quality of the perf report is affected by the quality of the scheduling models.

[Andrea Di Biagio via llvm-commits]

Author: adibiagio
Date: Wed Jun 19 09:10:58 2019
New Revision: 363830

URL: http://llvm.org/viewvc/llvm-project?rev=363830&view=rev
Log:
[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

Modified:
    llvm/trunk/docs/CommandGuide/llvm-mca.rst

Modified: llvm/trunk/docs/CommandGuide/llvm-mca.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/CommandGuide/llvm-mca.rst?rev=363830&r1=363829&r2=363830&view=diff
==============================================================================
--- llvm/trunk/docs/CommandGuide/llvm-mca.rst (original)
+++ llvm/trunk/docs/CommandGuide/llvm-mca.rst Wed Jun 19 09:10:58 2019
@@ -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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