syncsnoop_example.txt

Demonstrations of syncsnoop, the Linux eBPF/bcc version.

This program traces calls to the kernel sync(),fsync(),fdatasync(),syncfs(),
sync_file_range(),msync() routine, with basic timestamps:

$ sudo ./syncsnoop.py
TIME(s)            COMM             CALL
1173253.856512000  worker           fdatasync
1173253.858791000  worker           fdatasync
1173260.193706000  sync             sync
1173261.478894000  syncfs           syncfs
1173264.231075000  fsync            fsync
1173264.297788000  fsync            fdatasync
1173266.303600000  fdatasync        fsync
1173266.372047000  fdatasync        fdatasync
1173284.063700000  worker           fdatasync
1173284.089607000  worker           fdatasync
1173288.229822000  mkfs.ext4        fsync
1173288.304501000  mkfs.ext4        fsync
1173288.308225000  mkfs.ext4        fsync
1173288.315048000  mkfs.ext4        fsync
1173304.818227000  worker           fdatasync
1173304.885796000  worker           fdatasync
1173304.890055000  worker           fdatasync
1173304.893487000  worker           fdatasync
1173305.351074000  worker           fdatasync
1173305.359278000  worker           fdatasync
1173314.272416000  worker           fdatasync
1173314.301972000  worker           fdatasync
1173315.065319000  journal-offline  fsync
1173315.065367000  journal-offline  fsync
1173315.107918000  journal-offline  fsync
1173315.117972000  journal-offline  fsync
1173330.613072000  vim              fsync
1173337.763989000  vim              fsync
1173343.513054000  vim              fsync
1173344.479574000  worker           fdatasync
1173344.484815000  worker           fdatasync
1173345.040061000  systemd-journal  fsync
1173374.477736000  vim              fsync
1173374.688049000  worker           fdatasync
1173374.696112000  worker           fdatasync
1173391.717910000  vim              fsync
1173400.458152000  vim              fsync
1173404.895497000  worker           fdatasync
1173404.920379000  worker           fdatasync
1173404.946869000  worker           fdatasync
1173416.849539000  vim              fsync
1173422.885377000  vim              fsync
1173427.481849000  sync_file_range  sync_file_range
1173435.104840000  worker           fdatasync
1173435.131895000  worker           fdatasync
1173435.158102000  worker           fdatasync
1173449.246568000  vim              fsync
^C

This can be useful to identify that sync(),fsync(),fdatasync(),syncfs(),
sync_file_range(),msync() is being called, and its frequency.