On Thu, Feb 28, 2019 at 11:35:24AM +0300, Alexey Budankov wrote: > > The patch set implements runtime trace compression (-z option) in > record mode and trace auto decompression in report and inject modes. > Streaming Zstandard (Zstd) API (zstd) is used for compression and > decompression of data that come from kernel mmaped data buffers. > > Usage of implemented -z,--compression_level=n option provides ~3-5x > avg. trace file size reduction on variety of tested workloads what > saves storage space on larger server systems where trace file size > can easily reach several tens or even hundreds of GiBs, especially > when profiling with dwarf-based stacks and tracing of context switches. > Implemented -f,--mmap-flush option can be used to avoid compressing > every single byte of data and increase compression ratio at the same > time lowering tool runtime overhead. Default option value is 1 what > is equal to the current perf record implementation. The option is > independent from -z setting and doesn't vary with compression level: > > $ tools/perf/perf record -z 1 -e cycles -- matrix.gcc > $ tools/perf/perf record --aio=1 -z 1 -e cycles -- matrix.gcc > $ tools/perf/perf record -z 1 -f 1024 -e cycles -- matrix.gcc > $ tools/perf/perf record --aio=1 -z 1 -f 1024 -e cycles -- matrix.gcc
please make the 'z' option to choose some default value, so it's possible just to run: perf record -z ... to get comrpessed data.. not sure which strategy to use, probably the fastest '-z 1' as default with some warning about using that default value perhaps jirka
