[flang-commits] [PATCH] D118649: [flang] runtime perf: larger I/O buffer growth increments

[Peter Klausler via Phabricator via flang-commits]

klausler created this revision.
klausler added a reviewer: vdonaldson.
klausler added a project: Flang.
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klausler requested review of this revision.

When reallocating an I/O buffer to accommodate a large record,
ensure that the amount of growth is at least as large as the
minimum initial record size (64KiB).  The previous policy was
causing input buffer reallocation for each byte after the minimum
buffer size when scanning input data for record termination
newlines.


https://reviews.llvm.org/D118649

Files:
  flang/runtime/buffer.h


Index: flang/runtime/buffer.h
===================================================================
--- flang/runtime/buffer.h
+++ flang/runtime/buffer.h
@@ -135,7 +135,7 @@
     if (bytes > size_) {
       char *old{buffer_};
       auto oldSize{size_};
-      size_ = std::max<std::int64_t>(bytes, minBuffer);
+      size_ = std::max<std::int64_t>(bytes, size_ + minBuffer);
       buffer_ =
           reinterpret_cast<char *>(AllocateMemoryOrCrash(terminator, size_));
       auto chunk{std::min<std::int64_t>(length_, oldSize - start_)};


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