| 74 | | === OProfile Legacy Mode (cns3xxx) === |
| 75 | | The legacy mode (for CPU's that do not implement the new perf_events kernel profiling API. The Gateworks Laguna family using the Cavium cns3xxx CPU falls into this category. |
| 76 | | |
| 77 | | The legacy mode tools consists of: |
| 78 | | * oprofile kernel module (requires CONFIG_PROFILING=y and CONFIG_OPROFILE=m) |
| 79 | | * opcontrol - used to setup profiling (need vmlinux file) |
| 80 | | * opprofiled - the daemon (controlled via opcontrol) |
| 81 | | * opreport - report on collected samples |
| 82 | | opcontrol parameters: |
| 83 | | * --session-dir specifies the location to store samples. It defaults to /var/lib/oprofile and you can use this (with both opcontrol and opreport) to use samples from alternate locations |
| 84 | | * --separate specifies how to seperate samples. By default they are all stored in a single file (none), but you can choose to store by: |
| 85 | | - none - no profile separation (default) |
| 86 | | - lib - per-application profiles for libraries |
| 87 | | - kernel - per-application profiles for the kernel and kernel modules |
| 88 | | - thread - profiles for each thread and each task |
| 89 | | - cpu - profiles for each CPU |
| 90 | | - all - all of the above |
| 91 | | * Using profile specification parameters you can choose how to sample and report data" |
| 92 | | - cpu:0 - report just cpu0 (assuming data was collected separately (see above)) |
| 93 | | * --vmlinux=file (both for opcontrol and opreport) specifies the vmlinux kernel image required for decrypting kernel symbols |
| 94 | | * --setup will store the following list of parameters in /root/.oprofile/daemonrc to be used as default settings for opcontrol and opreport. Alternatively you can specify setup options to each program as needed |
| 95 | | |
| 96 | | Example usage: |
| 97 | | 1. copy your current kernel's vmlinux to /tmp |
| 98 | | 2. (optional) setup our configuration for vmlinux symbol decrypting, specific session location, and separating events by cpu: |
| 99 | | {{{#!bash |
| 100 | | opcontrol --setup --vmlinux=/tmp/vmlinux --session-dir=/tmp/session1 --separate=cpu |
| 101 | | }}} |
| 102 | | 3. start capturing events: |
| 103 | | {{{#!bash |
| 104 | | opcontrol --start |
| 105 | | }}} |
| 106 | | * you can force a flush of collected events via opcontrol --dump at any time |
| 107 | | * you can clearout current collected events via opcontrol --reset at any time |
| 108 | | 4. stop capturing events (and flush data): |
| 109 | | {{{#!bash |
| 110 | | opcontrol --shutdown |
| 111 | | }}} |
| 112 | | 5. report events: |
| 113 | | {{{#!bash |
| 114 | | opreport --vmlinux=/tmp/vmlinux --session-dir=/tmp/session1 |
| 115 | | }}} |
| 116 | | * if capturing events from individual cpu's separately (as shown above) you can show the info for just cpu0 via opreport cpu:0 |
| 117 | | * Note that opreport doesn't make use of the conf file generated by opcontrol --setup |
| 118 | | |
| 119 | | Important notes: |
| 120 | | * because the cns3xxx kernel and/or hardware does not support a performance counter and this means we are forced into timer based mode using timer irq. In this mode profiling is not useful when using code that disables irqs or runs in hardirq context |
| 121 | | |
| 122 | | References: |
| 123 | | * http://oprofile.sourceforge.net/doc/controlling-daemon.html |
| 124 | | * http://oprofile.sourceforge.net/doc/getting-started-with-legacy.html |
