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authorRui Ueyama <ruiu@google.com>2016-12-04 02:34:29 +0000
committerRui Ueyama <ruiu@google.com>2016-12-04 02:34:29 +0000
commit28f22ae15eb3df52138b5d15cfb435debf7a144f (patch)
treefdb9ac5ccb7f849ac12666fc12ed4c43c699524d /lld/ELF/Threads.h
parent697e7cd7610530eca1d3c729825cdd07e9b3d554 (diff)
downloadbcm5719-llvm-28f22ae15eb3df52138b5d15cfb435debf7a144f.tar.gz
bcm5719-llvm-28f22ae15eb3df52138b5d15cfb435debf7a144f.zip
Update comment to clarify the machine spec.
llvm-svn: 288609
Diffstat (limited to 'lld/ELF/Threads.h')
-rw-r--r--lld/ELF/Threads.h9
1 files changed, 5 insertions, 4 deletions
diff --git a/lld/ELF/Threads.h b/lld/ELF/Threads.h
index 58d24970e7b..c03e15253e1 100644
--- a/lld/ELF/Threads.h
+++ b/lld/ELF/Threads.h
@@ -19,7 +19,8 @@
//
// Fortunately, when a linker links large programs (when the link time is
// most critical), it spends most of the time to work on massive number of
-// small pieces of data of the same kind. Here are examples:
+// small pieces of data of the same kind, and there are opportunities for
+// large parallelism there. Here are examples:
//
// - We have hundreds of thousands of input sections that need to be
// copied to a result file at the last step of link. Once we fix a file
@@ -43,9 +44,9 @@
// The above approach seems to be working fairly well. As an example, when
// linking Chromium (output size 1.6 GB), using 4 cores reduces latency to
// 75% compared to single core (from 12.66 seconds to 9.55 seconds) on my
-// machine. Using 40 cores reduces it to 63% (from 12.66 seconds to 7.95
-// seconds). Because of the Amdahl's law, the speedup is not linear, but
-// as you add more cores, it gets faster.
+// Ivy Bridge Xeon 2.8 GHz machine. Using 40 cores reduces it to 63% (from
+// 12.66 seconds to 7.95 seconds). Because of the Amdahl's law, the
+// speedup is not linear, but as you add more cores, it gets faster.
//
// On a final note, if you are trying to optimize, keep the axiom "don't
// guess, measure!" in mind. Some important passes of the linker are not
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