[PATCH] D50882: [ThinLTO] Correct documentation on default number of threads

[Teresa Johnson via Phabricator via cfe-commits]

tejohnson created this revision.
tejohnson added a reviewer: pcc.
Herald added subscribers: dexonsmith, steven_wu, eraman, inglorion, mehdi_amini.

The number of threads used for ThinLTO backend parallelism was
dropped to the number of cores in r284618 to avoid oversubscribing
physical cores due to hyperthreading. This updates the documentation
to reflect that change.

Fixes PR38610.


Repository:
  rC Clang

https://reviews.llvm.org/D50882

Files:
  docs/ThinLTO.rst


Index: docs/ThinLTO.rst
===================================================================
--- docs/ThinLTO.rst
+++ docs/ThinLTO.rst
@@ -105,7 +105,9 @@
 -------------------------------
 .. _parallelism:
 
-By default, the ThinLTO link step will launch up to
+By default, the ThinLTO link step will launch as many
+threads in parallel as there are cores. If the number of
+cores can't be computed for the architecture, then it will launch
 ``std::thread::hardware_concurrency`` number of threads in parallel.
 For machines with hyper-threading, this is the total number of
 virtual cores. For some applications and machine configurations this


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