On 13.03.2019 17:37, Jiri Olsa wrote: > 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
in v8. ~Alexey > > jirka >
