On Mon, Feb 11, 2019 at 11:22:38PM +0300, Alexey Budankov wrote: SNIP
> static void record__init_features(struct record *rec) > @@ -838,6 +881,9 @@ static void record__init_features(struct record *rec) > if (!(rec->opts.use_clockid && rec->opts.clockid_res_ns)) > perf_header__clear_feat(&session->header, HEADER_CLOCKID); > > + if (!record__comp_enabled(rec)) > + perf_header__clear_feat(&session->header, HEADER_COMPRESSED); > + > perf_header__clear_feat(&session->header, HEADER_STAT); > } > > @@ -1147,6 +1193,10 @@ static int __cmd_record(struct record *rec, int argc, > const char **argv) > fd = perf_data__fd(data); > rec->session = session; > > + rec->opts.comp_level = 0; > + session->header.env.comp_level = rec->opts.comp_level; > + session->header.env.comp_type = PERF_COMP_NONE; hum I think both record and session are zerod from start, so this seems superfluous SNIP > diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c > index dec6d218c31c..5ad3a27a042f 100644 > --- a/tools/perf/util/header.c > +++ b/tools/perf/util/header.c > @@ -1463,6 +1463,21 @@ static int write_mem_topology(struct feat_fd *ff > __maybe_unused, > return ret; > } > > +static int write_compressed(struct feat_fd *ff __maybe_unused, > + struct perf_evlist *evlist __maybe_unused) > +{ > + int ret; > + u64 compression_info = ((u64)ff->ph->env.comp_type << 32) | > ff->ph->env.comp_level; > + > + ret = do_write(ff, &compression_info, sizeof(compression_info)); > + if (ret) > + return ret; > + > + compression_info = ((u64)ff->ph->env.comp_ratio << 32) | > ff->ph->env.comp_mmap_len; let's not complicate this, if you have two u32 values to store, store two u32 values ;-) also please add version in case we will add new fields in the future, so we can stay backward compatible jirka