* [LTP] Checking special execution durations for the determination of mountable file systems
@ 2021-09-20 19:34 Markus Elfring
0 siblings, 0 replies; only message in thread
From: Markus Elfring @ 2021-09-20 19:34 UTC (permalink / raw)
To: ltp
Hello,
I came along the need to check unexpected software execution durations
at another place.
* Qt
https://doc.qt.io/qt-5/qstorageinfo.html#mountedVolumes
* KPMcore
https://github.com/KDE/kpmcore/blob/ce39e149040bce9782b91e532d041ca0c7548a77/src/fs/filesystem.cpp#L145
Example:
[Markus_Elfring@fedora mountedVolumes]$ time ./mountedVolumes
Number of eventually mounted filesystems: 43
real 3m3,561s
user 0m0,016s
sys 0m0,026s
I increased software analysis efforts accordingly.
https://github.com/namhyung/uftrace/
[Markus_Elfring@fedora mountedVolumes]$ time sudo uftrace record --data=/home/Markus_Elfring/Test/mountedVolumes/Probe-uftrace/ --nest-libcall --kernel --num-thread=4 ./mountedVolumes
Number of eventually mounted filesystems: 42
real 3m4,835s
user 0m0,346s
sys 0m3,549s
[Markus_Elfring@fedora ~]$ uftrace --data=Test/mountedVolumes/Probe-uftrace report --filter=QStorageInfo::mountedVolumes
Total time Self time Calls Function
========== ========== ========== ====================
3.000 m 478.403 us 1 QStorageInfo::mountedVolumes
3.000 m 38.261 us 90 QStorageInfo::QStorageInfo
3.000 m 10.244 ms 48 QStorageInfo::setPath
3.000 m 3.000 m 23 linux:schedule
3.000 m 1.030 m 48 statvfs64
1.030 m 1.315 ms 47 __x64_sys_statfs
45.887 ms 5.746 ms 944 QDirIterator::next
28.768 ms 3.691 ms 944 QFileInfo::symLinkTarget
19.421 ms 1.246 ms 3185 fgets
18.845 ms 659.323 us 1900 QFileInfo::isFile
18.035 ms 1.207 ms 950 statx
…
Another bit of background information:
The function “statvfs64” gets called by the function “QStorageInfoPrivate::retrieveVolumeInfo”
(which is called by the function “QStorageInfoPrivate::doStat” and so on).
https://github.com/bminor/glibc/blob/595c22ecd8e87a27fd19270ed30fdbae9ad25426/sysdeps/unix/sysv/linux/statvfs64.c#L27
https://code.woboq.org/qt5/qtbase/src/corelib/io/qstorageinfo_unix.cpp.html#_ZN19QStorageInfoPrivate18retrieveVolumeInfoEv
https://code.woboq.org/qt5/qtbase/src/corelib/io/qstorageinfo_unix.cpp.html#_ZN19QStorageInfoPrivate14mountedVolumesEv
Would you like to help with the clarification for the shown measurements?
Regards,
Markus
--
Mailing list info: https://lists.linux.it/listinfo/ltp
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2021-09-20 19:35 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-20 19:34 [LTP] Checking special execution durations for the determination of mountable file systems Markus Elfring
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.