From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.web.de (mout.web.de [212.227.15.4]) by sourceware.org (Postfix) with ESMTPS id B494F3858426 for ; Sun, 19 Sep 2021 06:40:30 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org B494F3858426 X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [192.168.1.2] ([2.244.80.218]) by smtp.web.de (mrweb003 [213.165.67.108]) with ESMTPSA (Nemesis) id 0MUF50-1mISYz1Jbe-00R1In for ; Sun, 19 Sep 2021 08:40:27 +0200 Message-ID: <2b184d53-9044-0e6c-b4db-b87606478026@web.de> Date: Sun, 19 Sep 2021 08:40:17 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.1.0 To: libc-help@sourceware.org Content-Language: en-GB From: Markus Elfring Subject: Checking special execution durations for the determination of mountable file systems Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: 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X-List-Received-Date: Sun, 19 Sep 2021 06:40:33 -0000 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/ce39e149040bce9782b91e532d041ca0c75= 48a77/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=3D= /home/Markus_Elfring/Test/mountedVolumes/Probe-uftrace/ --nest-libcall --k= ernel --num-thread=3D4 ./mountedVolumes Number of eventually mounted filesystems: 42 real 3m4,835s user 0m0,346s sys 0m3,549s [Markus_Elfring@fedora ~]$ uftrace --data=3DTest/mountedVolumes/Probe-uftr= ace report --filter=3DQStorageInfo::mountedVolumes Total time Self time Calls Function =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D 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 =E2=80=A6 Another bit of background information: The function =E2=80=9Cstatvfs64=E2=80=9D gets called by the function =E2= =80=9CQStorageInfoPrivate::retrieveVolumeInfo=E2=80=9D (which is called by= the function =E2=80=9CQStorageInfoPrivate::doStat=E2=80=9D and so on). https://github.com/bminor/glibc/blob/595c22ecd8e87a27fd19270ed30fdbae9ad25= 426/sysdeps/unix/sysv/linux/statvfs64.c#L27 https://code.woboq.org/qt5/qtbase/src/corelib/io/qstorageinfo_unix.cpp.htm= l#_ZN19QStorageInfoPrivate18retrieveVolumeInfoEv https://code.woboq.org/qt5/qtbase/src/corelib/io/qstorageinfo_unix.cpp.htm= l#_ZN19QStorageInfoPrivate14mountedVolumesEv Would you like to help with the clarification for the shown measurements? Regards, Markus