1TRACE-CMD-RESET(1) 2================== 3 4NAME 5---- 6trace-cmd-reset - turn off all Ftrace tracing to bring back full performance 7 8SYNOPSIS 9-------- 10*trace-cmd reset* ['OPTIONS'] 11 12DESCRIPTION 13----------- 14The trace-cmd(1) reset command turns off all tracing of Ftrace. This will 15bring back the performance of the system before tracing was enabled. This is 16necessary since 'trace-cmd-record(1)', 'trace-cmd-stop(1)' and 17'trace-cmd-extract(1)' do not disable the tracer, event after the data has 18been pulled from the buffers. The rational is that the user may want to 19manually enable the tracer with the Ftrace pseudo file system, or examine other 20parts of Ftrace to see what trace-cmd did. After the reset command happens, 21the data in the ring buffer, and the options that were used are all lost. 22 23OPTIONS 24------- 25Please note that the order that options are specified on the command line is 26significant. See EXAMPLES. 27 28*-b* 'buffer_size':: 29 When the kernel boots, the Ftrace ring buffer is of a minimal size (3 30 pages per CPU). The first time the tracer is used, the ring buffer size 31 expands to what it was set for (default 1.4 Megs per CPU). 32 33 If no more tracing is to be done, this option allows you to shrink the 34 ring buffer down to free up available memory. 35 36 trace-cmd reset -b 1 37 38 The buffer instance affected is the one (or ones) specified by the most 39 recently preceding *-B*, *-t*, or *-a* option: 40 41 When used after *-B*, resizes the buffer instance that precedes it on 42 the command line. 43 44 When used after *-a*, resizes all buffer instances except the top one. 45 46 When used after *-t* or before any *-B* or *-a*, resizes the top 47 instance. 48 49*-B* 'buffer-name':: 50 If the kernel supports multiple buffers, this will reset the trace for 51 only the given buffer. It does not affect any other buffer. This may be 52 used multiple times to specify different buffers. The top level buffer 53 will not be reset if this option is given (unless the *-t* option is 54 also supplied). 55 56*-a*:: 57 Reset the trace for all existing buffer instances. When this option 58 is used, the top level instance will not be reset unless *-t* is given. 59 60*-d*:: 61 This option deletes the instance buffer(s) specified by the most recently 62 preceding *-B* or *-a* option. Because the top-level instance buffer 63 cannot be deleted, it is invalid to use this immediatly following *-t* or 64 prior to any *-B* or *-a* option on the command line. 65 66*-t*:: 67 Resets the top level instance buffer. Without the *-B* or *-a* option 68 this is the same as the default. But if *-B* or *-a* is used, this is 69 required if the top level instance buffer should also be reset. 70 71EXAMPLES 72-------- 73 74Reset tracing for instance-one and set its per-cpu buffer size to 4096kb. 75Also deletes instance-two. The top level instance and any other instances 76remain unaffected: 77 78 trace-cmd reset -B instance-one -b 4096 -B instance-two -d 79 80Delete all instance buffers. Top level instance remains unaffected: 81 82 trace-cmd reset -a -d 83 84Delete all instance buffers and also reset the top instance: 85 86 trace-cmd reset -t -a -d 87 88Invalid. This command implies an attempt to delete the top instance: 89 90 trace-cmd reset -a -t -d 91 92Reset the top instance and set its per-cpu buffer size to 1024kb. If any 93instance buffers exist, they will be unaffected: 94 95 trace-cmd reset -b 1024 96 97 98SEE ALSO 99-------- 100trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1), trace-cmd-start(1), 101trace-cmd-stop(1), trace-cmd-extract(1), trace-cmd-split(1), 102trace-cmd-list(1), trace-cmd-listen(1) 103 104AUTHOR 105------ 106Written by Steven Rostedt, <[email protected]> 107 108RESOURCES 109--------- 110https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/ 111 112COPYING 113------- 114Copyright \(C) 2010 Red Hat, Inc. Free use of this software is granted under 115the terms of the GNU Public License (GPL). 116 117