You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
210 lines
6.3 KiB
210 lines
6.3 KiB
.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) |
|
|
|
|