On Wed, Nov 21, 2018 at 07:45:28AM +0000, Song Liu wrote: > 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.
actualy I think that now it works properly, if you turn on task and mmap events, you'll see the samples get resolved right after aux events are processed: [root@krava perf]# ./perf script --show-info --show-task-events --show-mmap-events ... swapper 0 [007] 620566.187355: 64821 cycles:ppp: ffffffffab0b4d7c [unknown] ([unknown]) ffffffffaba01b1f [unknown] ([unknown]) ffffffffab75d567 [unknown] ([unknown]) ffffffffab0e1f56 [unknown] ([unknown]) ffffffffab0e216f [unknown] ([unknown]) ffffffffab050dc7 [unknown] ([unknown]) ffffffffab0000d5 [unknown] ([unknown]) swapper 0 [000] 0.000000: PERF_RECORD_MMAP -1/0: [0xffffffffab000000(0x152c8000) @ 0xffffffffab000000]: x [kernel.kallsyms]_text swapper 0 [000] 0.000000: PERF_RECORD_MMAP -1/0: [0xffffffffc02c8000(0x4000) @ 0]: x /lib/modules/4.18.17-200.fc28.x86_64/kernel/drivers/thermal/int340x_thermal/int3403_thermal.ko.xz swapper 0 [000] 0.000000: PERF_RECORD_MMAP -1/0: [0xffffffffc02cd000(0x4000) @ 0]: x /lib/modules/4.18.17-200.fc28.x86_64/kernel/drivers/thermal/intel_pch_thermal.ko.xz ... ext4-rsv-conver 0 [000] 0.000000: PERF_RECORD_COMM: ext4-rsv-conver:989/989 perf 20063 [005] 620566.187438: 1056712 cycles:ppp: ffffffffab1f605d filemap_map_pages+0x9d (/usr/lib/debug/lib/modules/4.18.17-200.fc28.x86_64/vmlinux) ffffffffab23aaa8 __handle_mm_fault+0x1018 (/usr/lib/debug/lib/modules/4.18.17-200.fc28.x86_64/vmlinux) ffffffffab23ae7a handle_mm_fault+0xda (/usr/lib/debug/lib/modules/4.18.17-200.fc28.x86_64/vmlinux) ffffffffab06ac90 __do_page_fault+0x240 (/usr/lib/debug/lib/modules/4.18.17-200.fc28.x86_64/vmlinux) ffffffffab06af62 do_page_fault+0x32 (/usr/lib/debug/lib/modules/4.18.17-200.fc28.x86_64/vmlinux) ffffffffaba010ee page_fault+0x1e (/usr/lib/debug/lib/modules/4.18.17-200.fc28.x86_64/vmlinux) ... if you record with --overwrite and --tail-synthesize the aux events will go to the top of the perf.data, so all's good > > After digging into this, I found this issue is introduced by commit > a73e24d240bc136619d382b1268f34d75c9d25ce. right, we got rid of that, because it will store the 'current/live' server mmaps for report/script, which is not what you want > 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. > > Thoughts? maybe we should make --tail-synthesize non optionable for --overwrite, and get rid of that option completely.. Wang, any idea? but definitelly not allow that for non overwrite thanks, jirka