[strace/strace] inconsistancy between -r (relative time) and -T (syscall time) (Issue #206)

[tchernomax]

Hello

I am stracing apache with this procedure:
```
strace -ff -s 512 -o /space/OTHERS/apache_strace -r -T -p 7124 &> /dev/null &
apachectl graceful
sleep 20
kill %1
```

But in some trace I get:
```
     0.000008 semop(9764864, [{sem_num=0, sem_op=-1, sem_flg=SEM_UNDO}], 1) = 0 <9.685337>
     0.000022 epoll_wait(55, [{events=EPOLLIN, data={u32=450864712, u64=140480241182280}}], 3, 10000) = 1 <0.046295>
```

How the relative timestamp of epoll_wait can be 0.000022 while the syscall time of semop is 9.685337 ?

```
# src/strace -V
strace -- version 5.16
Copyright (c) 1991-2022 The strace developers <https://strace.io>.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Optional features enabled: no-m32-mpers no-mx32-mpers
```

Any idea ?

note: same with `-tt` options
```
20:37:49.050065 (+     0.000012) semop(9928704, [{sem_num=0, sem_op=-1, sem_flg=SEM_UNDO}], 1) = 0 <5.030807>
20:37:54.080941 (+     0.000039) epoll_wait(55, [{events=EPOLLIN, data={u32=450864760, u64=140480241182328}}], 3, 10000) = 1 <0.136024>
```

-- 
Reply to this email directly or view it on GitHub:
https://github.com/strace/strace/issues/206
You are receiving this because you are subscribed to this thread.

Message ID: <strace/strace/issues/206 at github.com>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.strace.io/pipermail/strace-devel/attachments/20220114/a2ae7e7d/attachment.htm>