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diff --git a/doc/btrecord.8 b/doc/btrecord.8 new file mode 100644 index 0000000..c0655ab --- /dev/null +++ b/doc/btrecord.8 @@ -0,0 +1,210 @@ +.TH BTRECORD 8 "December 8, 2007" "blktrace git\-20071207142532" "" + + +.SH NAME +btrecord \- recreate IO loads recorded by blktrace + + +.SH SYNOPSIS +.B Usage: + +btrecord [ \fIoptions\fR ] <\fIdev\fR...> + + +.SH DESCRIPTION + +.P +The \fIbtrecord\fR and \fIbtreplay\fR tools provide the ability to +record and replay IOs captured by the \fIblktrace\fR utility. Attempts +are made to maintain ordering, CPU mappings and time-separation of IOs. + + +.P +The \fIblktrace\fR utility provides the ability to collect detailed +traces from the kernel for each IO processed by the block IO layer. The +traces provide a complete timeline for each IO processed, including +detailed information concerning when an IO was first received by the block +IO layer \(em indicating the device, CPU number, time stamp, IO direction, +sector number and IO size (number of sectors). Using this information, +one is able to \fBreplay\fR the IO again on the same machine or another +set up entirely. + +.P +The basic operating work-flow to replay IOs would be something like: + +.IP \- 2 + Run \fIblktrace\fR to collect traces. Here you specify the + device or devices that you wish to trace and later replay IOs upon. Note: + the only traces you are interested in are \fBQUEUE\fR requests \(em + thus, to save system resources (including storage for traces), one could + specify the \fI-a queue\fR command line option to \fIblktrace\fR. + +.IP \- 2 + While \fIblktrace\fR is running, you run the workload that you + are interested in. + +.IP \- 2 + When the work load has completed, you stop the \fIblktrace\fR + utility (thus saving all traces over the complete workload). + +.IP \- 2 + You extract the pertinent IO information from the traces saved by + \fIblktrace\fR using the \fIbtrecord\fR utility. This will parse + each trace file created by \fIblktrace\fR, and crafty IO descriptions + to be used in the next phase of the workload processing. + +.IP \- 2 + Once \fIbtrecord\fR has successfully created a series of data + files to be processed, you can run the \fIbtreplay\fR utility which + attempts to generate the same IOs seen during the sample workload phase. + + +.SH OPTIONS + +\-d <\fIdir\fR> +.br +\-\-input\-directory=<\fIdir\fR> +.RS +Set input directory. +This option requires a single parameter providing the directory +name for where input files are to be found. The default directory is the +current directory (\fI.\fR). +.RE + +\-D <\fIdir\fR> +.br +\-\-output\-directory=<\fIdir\fR> +.RS +Set output directory. +This option requires a single parameter providing the directory +name for where output files are to be found. The default directory is the +current directory (\fI.\fR). +.RE + +\-F +.br +\-\-find\-traces +.RS +Find trace files automatically +This option instructs \fIbtreplay\fR to go find all the trace files in the +directory specified (either via the \fI-d\fR option, or in the default +directory (\fI.\fR). +.RE + +\-h +.br +\-\-help +.RS +Show help and exit. +.RE + +\-V +.br +\-\-version +.RS +Show version number and exit. +.RE + +\-m <\fInanoseconds\fR> +.br +\-\-input\-base=<\fInanoseconds\fR> +.RS +The \fI\-m\fR option requires a single parameter which specifies an +amount of time (in nanoseconds) to include in any one bunch of IOs that +are to be processed. The smaller the value, the smaller the number of +IOs processed at one time \(em perhaps yielding in more realistic replay. +However, after a certain point the amount of overhead per bunch may result +in additional real replay time, thus yielding less accurate replay times. +.P +The default value is 10,000,000 nanoseconds (10 milliseconds). +.RE + +\-M <\fInum\fR> +.br +\-\-max\-pkts=<\fInum\fR> +.RS +Set maximum number of packets per bunch. +The \fI\-M\fR option requires a single parameter which specifies the +maximum number of IOs to store in a single bunch. As with the \fI\-m\fR +option, smaller values may or may not yield more accurate replay times. + +The default value is 8, with a maximum value of up to 512 being supported. +.RE + +\-o <\fIbasename\fR> +.br +\-\-output\-base=<\fIbasename\fR> +.RS +Set base name for output files. +Each output file has 3 fields: +.IP 1. 3 + Device identifier (taken directly from the device name of the + \fIblktrace\fR output file). +.IP 2. 3 + \fIbtrecord\fR base name \(em by default ``replay''. +.IP 3. 3 + The CPU number (again, taken directly from the + \fIblktrace\fR output file name). +.P +This option requires a single parameter that will override the default name +(replay), and replace it with the specified value. +.RE + +\-v +.br +\-\-verbose +.RS +Enable verbose output. +This option will output some simple statistics at the end of a successful +run. Example output is: +.nf +.P +sdab:0: 580661 pkts (tot), 126030 pkts (replay), 89809 bunches, 1.4 pkts/bunch +sdab:1: 2559775 pkts (tot), 430172 pkts (replay), 293029 bunches, 1.5 pkts/bunch +sdab:2: 653559 pkts (tot), 136522 pkts (replay), 102288 bunches, 1.3 pkts/bunch +sdab:3: 474773 pkts (tot), 117849 pkts (replay), 69572 bunches, 1.7 pkts/bunch +.fi +.P +The meaning of the columns is: +.IP 1. 3 + The first field contains the device name and CPU identifier. Thus: + \fIsdab:0:\fR means the device \fIsdab\fR and traces on CPU 0. +.IP 2. + The second field contains the total number of packets processed for each + device file. +.IP 3. + The next field shows the number of packets eligible for replay. +.IP 4. + The fourth field contains the total number of IO bunches. +.IP 5. + The last field shows the average number of IOs per bunch recorded. +.RE + + +.SH AUTHORS +\fIbtrecord\fR was written by Alan D. Brunelle. This +man page was created from the \fIbtreplay\fR documentation by Bas Zoetekouw. + + +.SH "REPORTING BUGS" +Report bugs to <linux\-btrace@vger.kernel.org> + +.SH COPYRIGHT +Copyright \(co 2007 Alan D. Brunelle, Alan D. Brunelle and Nathan Scott. +.br +This is free software. You may redistribute copies of it under the terms of +the GNU General Public License <http://www.gnu.org/licenses/gpl.html>. +There is NO WARRANTY, to the extent permitted by law. +.br +This manual page was created for Debian by Bas Zoetekouw. It was derived from +the documentation provided by the authors and it may be used, distributed and +modified under the terms of the GNU General Public License, version 2. +.br +On Debian systems, the text of the GNU General Public License can be found in +/usr/share/common\-licenses/GPL\-2. + +.SH "SEE ALSO" +The full documentation for btreplay can be found in /usr/share/doc/blktrace on Debian systems. +.br +blktrace (8), blkparse (1), btreplay (8) + |