[Docs] Increase Doxygen cache size

Summary:
When building Doxygen docs for llvm and clang, it helpfully prints a warning at
the end noting that the `LOOKUP_CACHE_SIZE` value was too small to keep all
symbols in memory.

By increasing to the size it recommends, Doxygen builds have greatly improved
performance. On my machine, time to run `doxygen-llvm` changes from 34 minutes
to 22 minutes, which is a decent amount of time saved by changing a single
number.

Reviewed By: hintonda

Patch by J. Ryan Stinnett!

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D62138

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361343 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/docs/doxygen.cfg.in b/docs/doxygen.cfg.in
index fc11f6863ac8158c9eadcad8f8a188f5e0ce192d..a8e84a31276257e8918c00edf0e4eef56274d515 100644 (file)
--- a/docs/doxygen.cfg.in
+++ b/docs/doxygen.cfg.in
@@ -385,7 +385,7 @@ TYPEDEF_HIDES_STRUCT   = NO
 # the optimal cache size from a speed point of view.
 # Minimum value: 0, maximum value: 9, default value: 0.
 
-LOOKUP_CACHE_SIZE      = 2
+LOOKUP_CACHE_SIZE      = 4
 
 #---------------------------------------------------------------------------
 # Build related configuration options