drsnoop(8) System Manager's Manual drsnoop(8)
NAME
drsnoop - Trace direct reclaim events. Uses Linux eBPF/bcc.
SYNOPSIS
drsnoop [-h] [-T] [-U] [-p PID] [-t TID] [-u UID] [-d DURATION] [-n
name] [-v]
DESCRIPTION
drsnoop trace direct reclaim events, showing which processes are alloc-
ing pages with direct reclaiming. This can be useful for discovering
when allocstall (/p- roc/vmstat) continues to increase, whether it is
caused by some critical proc- esses or not.
This works by tracing the direct reclaim events using kernel trace-
points.
This makes use of a Linux 4.4 feature (bpf_perf_event_output()); for
kernels older than 4.4, see the version under tools/old, which uses an
older mechanism.
Since this uses BPF, only the root user can use this tool.
REQUIREMENTS
CONFIG_BPF and bcc.
OPTIONS
-h Print usage message.
-T Include a timestamp column.
-U Show UID.
-p PID Trace this process ID only (filtered in-kernel).
-t TID Trace this thread ID only (filtered in-kernel).
-u UID Trace this UID only (filtered in-kernel).
-d DURATION
Total duration of trace in seconds.
-n name
Only print processes where its name partially matches 'name' -v
verbose Run in verbose mode. Will output system memory state
-v show system memory state
EXAMPLES
Trace all direct reclaim events:
# drsnoop
Trace all direct reclaim events, for 10 seconds only:
# drsnoop -d 10
Trace all direct reclaim events, and include timestamps:
# drsnoop -T
Show UID:
# drsnoop -U
Trace PID 181 only:
# drsnoop -p 181
Trace UID 1000 only:
# drsnoop -u 1000
Trace all direct reclaim events from processes where its name partially
match-
es 'mond': # drnsnoop -n mond
FIELDS
TIME(s)
Time of the call, in seconds.
UID User ID
PID Process ID
TID Thread ID
COMM Process name
OVERHEAD
This traces the kernel direct reclaim tracepoints and prints output for
each event. As the rate of this is generally expected to be low (<
1000/s), the overhead is also expected to be negligible.
SOURCE
This is from bcc.
https://github.com/iovisor/bcc
Also look in the bcc distribution for a companion _examples.txt file
containing example usage, output, and commentary for this tool.
OS
Linux
STABILITY
Unstable - in development.
AUTHOR
Wenbo Zhang
USER COMMANDS 2019-02-20 drsnoop(8)
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