Reduce memory allocations during endpoint restore #12405
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The GetCiliumVersionString function is only used in a single function within this package. Move it where it is used to reduce the package size of pkg/common which is imported all over the place. Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
The way endpoint state currently is restored from header files could potentially lead to a lot of memory allocations, partially due to the fact that the respective base64 encoded state is converted to a string after being read and then converted back to a byte slice in order to decode it. Since every conversion of a byte slice to a string allocates (due to the fact that strings are immutable in Go), this essentially doubles the memory that is used which could lead to memory allocation spikes during restore. Avoid this by reading the base64 encoded endpoint state into a byte slice directly and thus reducing the size and number of allocations. Before: EndpointSuite.BenchmarkReadEPsFromDirNames 5000 399980 ns/op 83665 B/op 743 allocs/op After: EndpointSuite.BenchmarkReadEPsFromDirNames 5000 369643 ns/op 73479 B/op 731 allocs/op Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
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First commit is preparatory and moves a function from
pkg/commoninto
pkg/endpointwhich is only used there.Second commit avoids excessive allocations during endpoint restore:
The way endpoint state currently is restored from header files could
potentially lead to a lot of memory allocations, partially due to the fact
that the respective base64 encoded state is converted to a string after
being read and then converted back to a byte slice in order to decode
it. Since every conversion of a byte slice to a string allocates (due to
the fact that strings are immutable in Go), this essentially doubles the
memory that is used which could lead to memory allocation spikes during
restore.
Avoid this by reading the base64 encoded endpoint state into a
byte slice directly and thus reducing the size and number of
allocations.
Before:
After:
For #12367 to slightly reduce chances of OOM.