zlib: use Z_DEFAULT_STRATEGY by default instead of Z_FIXED #10676
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Since Envoy::Compressor::ZlibCompressorImpl::CompressionStrategy is simply static_cast'ed to uint64_t the Standard strategy (4) becomes Z_FIXED (4 as well). This basically disables the use of dynamic Huffman codes when the gzip filter is configured to use default values. Make the Standard strategy equal to 0 to translate to Z_DEFAULT_STRATEGY. Contributes to envoyproxy#8448 Signed-off-by: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
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/cc @rgs1 |
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Nice, this doesn't make my benchmarks go faster but it does compress a bit better. |
mattklein123
requested changes
Apr 7, 2020
| @@ -50,7 +50,7 @@ class ZlibCompressorImpl : public Zlib::Base, public Compressor { | |||
| Filtered = 1, | |||
| Huffman = 2, | |||
| Rle = 3, | |||
| Standard = 4, | |||
| Standard = 0, | |||
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Please add a comment on why this is done this way. Also, does this need a release note?
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I put the defines from zlib.h instead of magic numbers. I think they are self-descriptive enough.
Signed-off-by: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
Signed-off-by: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
mattklein123
reviewed
Apr 8, 2020
| @@ -91,6 +91,9 @@ Version history | |||
| restart Envoy. The behavior will not switch until the connection pools are recreated. The new | |||
| circuit breaker behavior is described :ref:`here <arch_overview_circuit_break>`. | |||
| * upstream: changed load distribution algorithm when all priorities enter :ref:`panic mode<arch_overview_load_balancing_panic_threshold>`. | |||
| * zlib: by default zlib is initialized to use its default strategy (Z_DEFAULT_STRATEGY) | |||
| instead of the fixed one (Z_FIXED). The difference is that the use of dynammic | |||
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note to self: typo "dynammic". I will fix this when I do the release cleanup.
mattklein123
approved these changes
Apr 8, 2020
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Description:
Since
Envoy::Compressor::ZlibCompressorImpl::CompressionStrategyis simply static_cast'ed touint64_ttheStandardstrategy (4) becomesZ_FIXED(4 as well). This basically disables the use ofdynamic Huffman codes when the gzip filter is configured to use default values.
Make the
Standardstrategy equal to 0 to translate toZ_DEFAULT_STRATEGY.Contributes to #8448
Risk Level: Low
Testing: Manual testing