Messages in this thread | | | From | Song Liu <> | Subject | Re: perf tools: remove option --tail-synthesize ? | Date | Thu, 22 Nov 2018 18:18:15 +0000 |
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> On Nov 21, 2018, at 5:50 PM, Wangnan (F) <wangnan0@huawei.com> wrote: > > > > On 2018/11/21 21:11, Arnaldo Carvalho de Melo wrote: >> Em Wed, Nov 21, 2018 at 07:45:28AM +0000, Song Liu escreveu: >>> Hi, >>> >>> I found perf-record --tail-synthesize without --overwrite breaks symbols >>> for perf-script, perf-report, etc. For example: >>> >>> [root@]# ~/perf record -ag --tail-synthesize -- sleep 1 >>> [ perf record: Woken up 1 times to write data ] >>> [ perf record: Captured and wrote 1.129 MB perf.data (3531 samples) ] >>> [root@]# ~/perf script | head >>> swapper 0 [000] 1250675.051971: 1 cycles:ppp: >>> ffffffff81009e15 [unknown] ([unknown]) >>> ffffffff81196b19 [unknown] ([unknown]) >>> ffffffff81196579 [unknown] ([unknown]) >>> ffffffff81110ca7 [unknown] ([unknown]) >>> ffffffff81a01f4a [unknown] ([unknown]) >>> ffffffff81a017bf [unknown] ([unknown]) >>> ffffffff8180e17a [unknown] ([unknown]) >>> >>> perf-record with --overwrite does NOT have this issue. >>> >>> After digging into this, I found this issue is introduced by commit >>> a73e24d240bc136619d382b1268f34d75c9d25ce. >>> >>> Reverting this commit does fix this issue. However, on a second thought, >>> I feel it is probably better just drop --tail-synthesize, as it doesn't >>> make much sense without --overwrite. All we need is to do tail_synthesize >>> when --overwrite is set. >>> > > Some cases we use --overwrite without --tail-synthesize. How about setting > --tail-synthesize when selecting --overwrite by default, throw a warning > when --overwrite is not set and leave a --no-tail-synthesize option? >
--overwrite implies --tail-synthesize. So with --overwrite, it is always tail-synthesize. Do we really need --overwrite and --no-tail-synthesize? If not, we can probably just drop --tail-synthesize (or mark it as deprecated)?
Thanks, Song
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