On Tue, Nov 17, 2020 at 09:44:37AM -0300, Arnaldo Carvalho de Melo wrote: > Em Tue, Nov 17, 2020 at 12:00:42PM +0100, Jiri Olsa escreveu: > > Allow mmap2 event to synthesize kernel image, > > so we can synthesize kernel build id data in > > following changes. > > > > It's enabled by new symbol_conf.buildid_mmap2 > > bool, which will be switched in following > > changes. > > Why make this an option? MMAP2 goes back years: > > 13d7a2410fa637f45 (Stephane Eranian 2013-08-21 12:10:24 +0200 904) > * The MMAP2 records are an augmented version of MMAP, they add > 13d7a2410fa637f45 (Stephane Eranian 2013-08-21 12:10:24 +0200 905) > * maj, min, ino numbers to be used to uniquely identify each mapping > > Also we unconditionally generate MMAP2 events if the kernel supports it, > from evsel__config(): > > attr->mmap = track; > attr->mmap2 = track && !perf_missing_features.mmap2; > > So perhaps we should reuse that logic? I.e. use mmap2 if the kernel > supports it?
mmap2 itself is not a problem, the problem is the new bit (PERF_RECORD_MISC_MMAP_BUILD_ID) that says there's build id in mmap2.. older perf tool won't understand that and report will crash jirka
