Messages in this thread | | | Subject | Re: [PATCH v10 09/12] perf record: implement -z,--compression_level[=<n>] option | From | Alexey Budankov <> | Date | Wed, 15 May 2019 18:44:29 +0300 |
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On 15.05.2019 15:59, Arnaldo Carvalho de Melo wrote: > Em Wed, May 15, 2019 at 11:43:30AM +0300, Alexey Budankov escreveu: >> On 15.05.2019 0:46, Arnaldo Carvalho de Melo wrote: >>> Em Tue, May 14, 2019 at 05:20:41PM -0300, Arnaldo Carvalho de Melo escreveu: >>>> Em Mon, Mar 18, 2019 at 08:44:42PM +0300, Alexey Budankov escreveu: > >>>>> Implemented -z,--compression_level[=<n>] option that enables compression >>>>> of mmaped kernel data buffers content in runtime during perf record >>>>> mode collection. Default option value is 1 (fastest compression). > >>> <SNIP> > >>>> [root@quaco ~]# perf record -z2 >>>> ^C[ perf record: Woken up 1 times to write data ] >>>> 0x1746e0 [0x76]: failed to process type: 81 [Invalid argument] >>>> [ perf record: Captured and wrote 1.568 MB perf.data, compressed (original 0.452 MB, ratio is 3.995) ] > >>>> [root@quaco ~]# > >>> So, its the buildid processing at the end, so we can't do build-id >>> processing when using PERF_RECORD_COMPRESSED, otherwise we'd have to >>> uncompress at the end to find the PERF_RECORD_FORK/PERF_RECORD_MMAP, >>> etc. > >>> [root@quaco ~]# perf record -z2 --no-buildid sleep 1 >>> [ perf record: Woken up 1 times to write data ] >>> [ perf record: Captured and wrote 0.020 MB perf.data, compressed (original 0.001 MB, ratio is 2.153) ] >>> [root@quaco ~]# perf report -D | grep PERF_RECORD_COMP >>> 0x4f40 [0x195]: failed to process type: 81 [Invalid argument] >>> Error: >>> failed to process sample >>> 0 0x4f40 [0x195]: PERF_RECORD_COMPRESSED >>> [root@quaco ~]# > >>> I'll play with it tomorrow. > >> Applied the whole patch set on top of the current perf/core >> and the whole thing functions as expected. > > It doesn't, see the reported error above, these three lines, that > shouldn't be there: > > 0x4f40 [0x195]: failed to process type: 81 [Invalid argument] > Error: > failed to process sample > > That is because at this point in the patch series a record was > introduced that is not being handled by the build id processing done, by > default, at the end of the 'perf record' session, and, as explained > above, needs fixing so that when we do 'git bisect' looking for a non > expected "failed to process type: 81" kind of error, this doesn't > appear. > > I added the changes below to this cset and will continue from there: > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index d84a4885e341..f8d21991f94c 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -2284,6 +2284,12 @@ int cmd_record(int argc, const char **argv) > "cgroup monitoring only available in system-wide mode"); > > } > + > + if (rec->opts.comp_level != 0) { > + pr_debug("Compression enabled, disabling build id collection at the end of the session\n"); > + rec->no_buildid = true; > + } > + > if (rec->opts.record_switch_events && > !perf_can_record_switch_events()) { > ui__error("kernel does not support recording context switch events\n"); > > --------------------------------------------------------------------------- > > [acme@quaco perf]$ perf record -z2 sleep 1 > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.001 MB perf.data, compressed (original 0.001 MB, ratio is 2.292) ] > [acme@quaco perf]$ perf record -v -z2 sleep 1 > Compression enabled, disabling build id collection at the end of the session > Using CPUID GenuineIntel-6-8E-A > nr_cblocks: 0 > affinity: SYS > mmap flush: 1 > comp level: 2 > mmap size 528384B > Couldn't start the BPF side band thread: > BPF programs starting from now on won't be annotatable > perf_event__synthesize_bpf_events: can't get next program: Operation not permitted > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.001 MB perf.data, compressed (original 0.001 MB, ratio is 2.305) ] > [acme@quaco perf]$ > > Will check if its possible to get rid of the following in this patch, to > keep bisection working for this case as well: > > [acme@quaco perf]$ perf report -D | grep COMPRESS > 0x1b8 [0x169]: failed to process type: 81 [Invalid argument] > Error: > failed to process sample > 0 0x1b8 [0x169]: PERF_RECORD_COMPRESSED > [acme@quaco perf]$
Makes sense. Thanks.
~Alexey
> > - Arnaldo >
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