diff options
| author | Julian Andres Klode <jak@debian.org> | 2016-01-07 16:16:06 +0100 |
|---|---|---|
| committer | Julian Andres Klode <jak@debian.org> | 2016-01-07 16:17:51 +0100 |
| commit | 40940e63a4dd3c7ef09ea1175e189350457b7270 (patch) | |
| tree | 07893b75aa7bd1ffad1fa252456117800e3d3516 | |
| parent | df46a87ab6b67019277884f7ae990af26080280d (diff) | |
CopyFile: Use 64 * 1024 instead of 64000 as buffer size
This is a multiple of the page size and thus results in less
page faults, speeding up copying.
Also, while we're at at, unify all uses of that size in a
constant variable APT_BUFFER_SIZE.
| -rw-r--r-- | apt-pkg/contrib/fileutl.cc | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc index de215a50b..a48447bea 100644 --- a/apt-pkg/contrib/fileutl.cc +++ b/apt-pkg/contrib/fileutl.cc @@ -78,6 +78,9 @@ using namespace std; +/* Should be a multiple of the common page size (4096) */ +static constexpr unsigned long long APT_BUFFER_SIZE = 64 * 1024; + // RunScripts - Run a set of scripts from a configuration subtree /*{{{*/ // --------------------------------------------------------------------- /* */ @@ -163,7 +166,7 @@ bool CopyFile(FileFd &From,FileFd &To) return false; // Buffered copy between fds - constexpr size_t BufSize = 64000; + constexpr size_t BufSize = APT_BUFFER_SIZE; std::unique_ptr<unsigned char[]> Buf(new unsigned char[BufSize]); unsigned long long ToRead = 0; do { @@ -1500,7 +1503,6 @@ public: }; /*}}}*/ class APT_HIDDEN Lz4FileFdPrivate: public FileFdPrivate { /*{{{*/ - static constexpr unsigned long long BLK_SIZE = 64 * 1024; static constexpr unsigned long long LZ4_HEADER_SIZE = 19; static constexpr unsigned long long LZ4_FOOTER_SIZE = 4; #ifdef HAVE_LZ4 @@ -1510,7 +1512,7 @@ class APT_HIDDEN Lz4FileFdPrivate: public FileFdPrivate { /*{{{*/ FileFd backend; simple_buffer lz4_buffer; // Count of bytes that the decompressor expects to read next, or buffer size. - size_t next_to_load = BLK_SIZE; + size_t next_to_load = APT_BUFFER_SIZE; public: virtual bool InternalOpen(int const iFd, unsigned int const Mode) override { @@ -1519,11 +1521,11 @@ public: if ((Mode & FileFd::WriteOnly) == FileFd::WriteOnly) { res = LZ4F_createCompressionContext(&cctx, LZ4F_VERSION); - lz4_buffer.reset(LZ4F_compressBound(BLK_SIZE, nullptr) + lz4_buffer.reset(LZ4F_compressBound(APT_BUFFER_SIZE, nullptr) + LZ4_HEADER_SIZE + LZ4_FOOTER_SIZE); } else { res = LZ4F_createDecompressionContext(&dctx, LZ4F_VERSION); - lz4_buffer.reset(64 * 1024); + lz4_buffer.reset(APT_BUFFER_SIZE); } filefd->Flags |= FileFd::Compressed; @@ -1591,7 +1593,7 @@ public: } virtual ssize_t InternalWrite(void const * const From, unsigned long long const Size) override { - unsigned long long const towrite = std::min(BLK_SIZE, Size); + unsigned long long const towrite = std::min(APT_BUFFER_SIZE, Size); res = LZ4F_compressUpdate(cctx, lz4_buffer.buffer, lz4_buffer.buffersize_max, @@ -1619,7 +1621,7 @@ public: { /* Reset variables */ res = 0; - next_to_load = BLK_SIZE; + next_to_load = APT_BUFFER_SIZE; if (cctx != nullptr) { |