diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/DocBook/debugobjects.tmpl | 2 | ||||
| -rw-r--r-- | Documentation/cdrom/packet-writing.txt | 2 | ||||
| -rw-r--r-- | Documentation/fault-injection/fault-injection.txt | 70 | ||||
| -rw-r--r-- | Documentation/kprobes.txt | 6 | ||||
| -rw-r--r-- | Documentation/trace/ftrace.txt | 233 | ||||
| -rw-r--r-- | Documentation/trace/mmiotrace.txt | 26 |
6 files changed, 195 insertions, 144 deletions
diff --git a/Documentation/DocBook/debugobjects.tmpl b/Documentation/DocBook/debugobjects.tmpl index 7f5f218015f..08ff908aa7a 100644 --- a/Documentation/DocBook/debugobjects.tmpl +++ b/Documentation/DocBook/debugobjects.tmpl @@ -106,7 +106,7 @@ number of errors are printk'ed including a full stack trace. </para> <para> - The statistics are available via debugfs/debug_objects/stats. + The statistics are available via /sys/kernel/debug/debug_objects/stats. They provide information about the number of warnings and the number of successful fixups along with information about the usage of the internal tracking objects and the state of the diff --git a/Documentation/cdrom/packet-writing.txt b/Documentation/cdrom/packet-writing.txt index cf1f8126991..1c407778c8b 100644 --- a/Documentation/cdrom/packet-writing.txt +++ b/Documentation/cdrom/packet-writing.txt @@ -117,7 +117,7 @@ Using the pktcdvd debugfs interface To read pktcdvd device infos in human readable form, do: - # cat /debug/pktcdvd/pktcdvd[0-7]/info + # cat /sys/kernel/debug/pktcdvd/pktcdvd[0-7]/info For a description of the debugfs interface look into the file: diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt index 4bc374a1434..07930564079 100644 --- a/Documentation/fault-injection/fault-injection.txt +++ b/Documentation/fault-injection/fault-injection.txt @@ -29,16 +29,16 @@ o debugfs entries fault-inject-debugfs kernel module provides some debugfs entries for runtime configuration of fault-injection capabilities. -- /debug/fail*/probability: +- /sys/kernel/debug/fail*/probability: likelihood of failure injection, in percent. Format: <percent> Note that one-failure-per-hundred is a very high error rate for some testcases. Consider setting probability=100 and configure - /debug/fail*/interval for such testcases. + /sys/kernel/debug/fail*/interval for such testcases. -- /debug/fail*/interval: +- /sys/kernel/debug/fail*/interval: specifies the interval between failures, for calls to should_fail() that pass all the other tests. @@ -46,18 +46,18 @@ configuration of fault-injection capabilities. Note that if you enable this, by setting interval>1, you will probably want to set probability=100. -- /debug/fail*/times: +- /sys/kernel/debug/fail*/times: specifies how many times failures may happen at most. A value of -1 means "no limit". -- /debug/fail*/space: +- /sys/kernel/debug/fail*/space: specifies an initial resource "budget", decremented by "size" on each call to should_fail(,size). Failure injection is suppressed until "space" reaches zero. -- /debug/fail*/verbose +- /sys/kernel/debug/fail*/verbose Format: { 0 | 1 | 2 } specifies the verbosity of the messages when failure is @@ -65,17 +65,17 @@ configuration of fault-injection capabilities. log line per failure; '2' will print a call trace too -- useful to debug the problems revealed by fault injection. -- /debug/fail*/task-filter: +- /sys/kernel/debug/fail*/task-filter: Format: { 'Y' | 'N' } A value of 'N' disables filtering by process (default). Any positive value limits failures to only processes indicated by /proc/<pid>/make-it-fail==1. -- /debug/fail*/require-start: -- /debug/fail*/require-end: -- /debug/fail*/reject-start: -- /debug/fail*/reject-end: +- /sys/kernel/debug/fail*/require-start: +- /sys/kernel/debug/fail*/require-end: +- /sys/kernel/debug/fail*/reject-start: +- /sys/kernel/debug/fail*/reject-end: specifies the range of virtual addresses tested during stacktrace walking. Failure is injected only if some caller @@ -84,26 +84,26 @@ configuration of fault-injection capabilities. Default required range is [0,ULONG_MAX) (whole of virtual address space). Default rejected range is [0,0). -- /debug/fail*/stacktrace-depth: +- /sys/kernel/debug/fail*/stacktrace-depth: specifies the maximum stacktrace depth walked during search for a caller within [require-start,require-end) OR [reject-start,reject-end). -- /debug/fail_page_alloc/ignore-gfp-highmem: +- /sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem: Format: { 'Y' | 'N' } default is 'N', setting it to 'Y' won't inject failures into highmem/user allocations. -- /debug/failslab/ignore-gfp-wait: -- /debug/fail_page_alloc/ignore-gfp-wait: +- /sys/kernel/debug/failslab/ignore-gfp-wait: +- /sys/kernel/debug/fail_page_alloc/ignore-gfp-wait: Format: { 'Y' | 'N' } default is 'N', setting it to 'Y' will inject failures only into non-sleep allocations (GFP_ATOMIC allocations). -- /debug/fail_page_alloc/min-order: +- /sys/kernel/debug/fail_page_alloc/min-order: specifies the minimum page allocation order to be injected failures. @@ -166,13 +166,13 @@ o Inject slab allocation failures into module init/exit code #!/bin/bash FAILTYPE=failslab -echo Y > /debug/$FAILTYPE/task-filter -echo 10 > /debug/$FAILTYPE/probability -echo 100 > /debug/$FAILTYPE/interval -echo -1 > /debug/$FAILTYPE/times -echo 0 > /debug/$FAILTYPE/space -echo 2 > /debug/$FAILTYPE/verbose -echo 1 > /debug/$FAILTYPE/ignore-gfp-wait +echo Y > /sys/kernel/debug/$FAILTYPE/task-filter +echo 10 > /sys/kernel/debug/$FAILTYPE/probability +echo 100 > /sys/kernel/debug/$FAILTYPE/interval +echo -1 > /sys/kernel/debug/$FAILTYPE/times +echo 0 > /sys/kernel/debug/$FAILTYPE/space +echo 2 > /sys/kernel/debug/$FAILTYPE/verbose +echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait faulty_system() { @@ -217,20 +217,20 @@ then exit 1 fi -cat /sys/module/$module/sections/.text > /debug/$FAILTYPE/require-start -cat /sys/module/$module/sections/.data > /debug/$FAILTYPE/require-end +cat /sys/module/$module/sections/.text > /sys/kernel/debug/$FAILTYPE/require-start +cat /sys/module/$module/sections/.data > /sys/kernel/debug/$FAILTYPE/require-end -echo N > /debug/$FAILTYPE/task-filter -echo 10 > /debug/$FAILTYPE/probability -echo 100 > /debug/$FAILTYPE/interval -echo -1 > /debug/$FAILTYPE/times -echo 0 > /debug/$FAILTYPE/space -echo 2 > /debug/$FAILTYPE/verbose -echo 1 > /debug/$FAILTYPE/ignore-gfp-wait -echo 1 > /debug/$FAILTYPE/ignore-gfp-highmem -echo 10 > /debug/$FAILTYPE/stacktrace-depth +echo N > /sys/kernel/debug/$FAILTYPE/task-filter +echo 10 > /sys/kernel/debug/$FAILTYPE/probability +echo 100 > /sys/kernel/debug/$FAILTYPE/interval +echo -1 > /sys/kernel/debug/$FAILTYPE/times +echo 0 > /sys/kernel/debug/$FAILTYPE/space +echo 2 > /sys/kernel/debug/$FAILTYPE/verbose +echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait +echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-highmem +echo 10 > /sys/kernel/debug/$FAILTYPE/stacktrace-depth -trap "echo 0 > /debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT +trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT echo "Injecting errors into the module $module... (interrupt to stop)" sleep 1000000 diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt index 1e7a769a10f..053037a1fe6 100644 --- a/Documentation/kprobes.txt +++ b/Documentation/kprobes.txt @@ -507,9 +507,9 @@ http://www.linuxsymposium.org/2006/linuxsymposium_procv2.pdf (pages 101-115) Appendix A: The kprobes debugfs interface With recent kernels (> 2.6.20) the list of registered kprobes is visible -under the /debug/kprobes/ directory (assuming debugfs is mounted at /debug). +under the /sys/kernel/debug/kprobes/ directory (assuming debugfs is mounted at //sys/kernel/debug). -/debug/kprobes/list: Lists all registered probes on the system +/sys/kernel/debug/kprobes/list: Lists all registered probes on the system c015d71a k vfs_read+0x0 c011a316 j do_fork+0x0 @@ -525,7 +525,7 @@ virtual addresses that correspond to modules that've been unloaded), such probes are marked with [GONE]. If the probe is temporarily disabled, such probes are marked with [DISABLED]. -/debug/kprobes/enabled: Turn kprobes ON/OFF forcibly. +/sys/kernel/debug/kprobes/enabled: Turn kprobes ON/OFF forcibly. Provides a knob to globally and forcibly turn registered kprobes ON or OFF. By default, all kprobes are enabled. By echoing "0" to this file, all diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt index 7bd27f0e288..a39b3c749de 100644 --- a/Documentation/trace/ftrace.txt +++ b/Documentation/trace/ftrace.txt @@ -7,7 +7,6 @@ Copyright 2008 Red Hat Inc. (dual licensed under the GPL v2) Reviewers: Elias Oltmanns, Randy Dunlap, Andrew Morton, John Kacur, and David Teigland. - Written for: 2.6.28-rc2 Introduction @@ -33,13 +32,26 @@ The File System Ftrace uses the debugfs file system to hold the control files as well as the files to display output. -To mount the debugfs system: +When debugfs is configured into the kernel (which selecting any ftrace +option will do) the directory /sys/kernel/debug will be created. To mount +this directory, you can add to your /etc/fstab file: + + debugfs /sys/kernel/debug debugfs defaults 0 0 + +Or you can mount it at run time with: + + mount -t debugfs nodev /sys/kernel/debug - # mkdir /debug - # mount -t debugfs nodev /debug +For quicker access to that directory you may want to make a soft link to +it: -( Note: it is more common to mount at /sys/kernel/debug, but for - simplicity this document will use /debug) + ln -s /sys/kernel/debug /debug + +Any selected ftrace option will also create a directory called tracing +within the debugfs. The rest of the document will assume that you are in +the ftrace directory (cd /sys/kernel/debug/tracing) and will only concentrate +on the files within that directory and not distract from the content with +the extended "/sys/kernel/debug/tracing" path name. That's it! (assuming that you have ftrace configured into your kernel) @@ -389,18 +401,18 @@ trace_options The trace_options file is used to control what gets printed in the trace output. To see what is available, simply cat the file: - cat /debug/tracing/trace_options + cat trace_options print-parent nosym-offset nosym-addr noverbose noraw nohex nobin \ noblock nostacktrace nosched-tree nouserstacktrace nosym-userobj To disable one of the options, echo in the option prepended with "no". - echo noprint-parent > /debug/tracing/trace_options + echo noprint-parent > trace_options To enable an option, leave off the "no". - echo sym-offset > /debug/tracing/trace_options + echo sym-offset > trace_options Here are the available options: @@ -476,11 +488,11 @@ sched_switch This tracer simply records schedule switches. Here is an example of how to use it. - # echo sched_switch > /debug/tracing/current_tracer - # echo 1 > /debug/tracing/tracing_enabled + # echo sched_switch > current_tracer + # echo 1 > tracing_enabled # sleep 1 - # echo 0 > /debug/tracing/tracing_enabled - # cat /debug/tracing/trace + # echo 0 > tracing_enabled + # cat trace # tracer: sched_switch # @@ -583,13 +595,13 @@ new trace is saved. To reset the maximum, echo 0 into tracing_max_latency. Here is an example: - # echo irqsoff > /debug/tracing/current_tracer - # echo 0 > /debug/tracing/tracing_max_latency - # echo 1 > /debug/tracing/tracing_enabled + # echo irqsoff > current_tracer + # echo 0 > tracing_max_latency + # echo 1 > tracing_enabled # ls -ltr [...] - # echo 0 > /debug/tracing/tracing_enabled - # cat /debug/tracing/latency_trace + # echo 0 > tracing_enabled + # cat latency_trace # tracer: irqsoff # irqsoff latency trace v1.1.5 on 2.6.26 @@ -690,13 +702,13 @@ Like the irqsoff tracer, it records the maximum latency for which preemption was disabled. The control of preemptoff tracer is much like the irqsoff tracer. - # echo preemptoff > /debug/tracing/current_tracer - # echo 0 > /debug/tracing/tracing_max_latency - # echo 1 > /debug/tracing/tracing_enabled + # echo preemptoff > current_tracer + # echo 0 > tracing_max_latency + # echo 1 > tracing_enabled # ls -ltr [...] - # echo 0 > /debug/tracing/tracing_enabled - # cat /debug/tracing/latency_trace + # echo 0 > tracing_enabled + # cat latency_trace # tracer: preemptoff # preemptoff latency trace v1.1.5 on 2.6.26-rc8 @@ -837,13 +849,13 @@ tracer. Again, using this trace is much like the irqsoff and preemptoff tracers. - # echo preemptirqsoff > /debug/tracing/current_tracer - # echo 0 > /debug/tracing/tracing_max_latency - # echo 1 > /debug/tracing/tracing_enabled + # echo preemptirqsoff > current_tracer + # echo 0 > tracing_max_latency + # echo 1 > tracing_enabled # ls -ltr [...] - # echo 0 > /debug/tracing/tracing_enabled - # cat /debug/tracing/latency_trace + # echo 0 > tracing_enabled + # cat latency_trace # tracer: preemptirqsoff # preemptirqsoff latency trace v1.1.5 on 2.6.26-rc8 @@ -999,12 +1011,12 @@ slightly differently than we did with the previous tracers. Instead of performing an 'ls', we will run 'sleep 1' under 'chrt' which changes the priority of the task. - # echo wakeup > /debug/tracing/current_tracer - # echo 0 > /debug/tracing/tracing_max_latency - # echo 1 > /debug/tracing/tracing_enabled + # echo wakeup > current_tracer + # echo 0 > tracing_max_latency + # echo 1 > tracing_enabled # chrt -f 5 sleep 1 - # echo 0 > /debug/tracing/tracing_enabled - # cat /debug/tracing/latency_trace + # echo 0 > tracing_enabled + # cat latency_trace # tracer: wakeup # wakeup latency trace v1.1.5 on 2.6.26-rc8 @@ -1114,11 +1126,11 @@ can be done from the debug file system. Make sure the ftrace_enabled is set; otherwise this tracer is a nop. # sysctl kernel.ftrace_enabled=1 - # echo function > /debug/tracing/current_tracer - # echo 1 > /debug/tracing/tracing_enabled + # echo function > current_tracer + # echo 1 > tracing_enabled # usleep 1 - # echo 0 > /debug/tracing/tracing_enabled - # cat /debug/tracing/trace + # echo 0 > tracing_enabled + # cat trace # tracer: function # # TASK-PID CPU# TIMESTAMP FUNCTION @@ -1155,7 +1167,7 @@ int trace_fd; [...] int main(int argc, char *argv[]) { [...] - trace_fd = open("/debug/tracing/tracing_enabled", O_WRONLY); + trace_fd = open(tracing_file("tracing_enabled"), O_WRONLY); [...] if (condition_hit()) { write(trace_fd, "0", 1); @@ -1163,26 +1175,20 @@ int main(int argc, char *argv[]) { [...] } -Note: Here we hard coded the path name. The debugfs mount is not -guaranteed to be at /debug (and is more commonly at -/sys/kernel/debug). For simple one time traces, the above is -sufficent. For anything else, a search through /proc/mounts may -be needed to find where the debugfs file-system is mounted. - Single thread tracing --------------------- -By writing into /debug/tracing/set_ftrace_pid you can trace a +By writing into set_ftrace_pid you can trace a single thread. For example: -# cat /debug/tracing/set_ftrace_pid +# cat set_ftrace_pid no pid -# echo 3111 > /debug/tracing/set_ftrace_pid -# cat /debug/tracing/set_ftrace_pid +# echo 3111 > set_ftrace_pid +# cat set_ftrace_pid 3111 -# echo function > /debug/tracing/current_tracer -# cat /debug/tracing/trace | head +# echo function > current_tracer +# cat trace | head # tracer: function # # TASK-PID CPU# TIMESTAMP FUNCTION @@ -1193,8 +1199,8 @@ no pid yum-updatesd-3111 [003] 1637.254683: lock_hrtimer_base <-hrtimer_try_to_cancel yum-updatesd-3111 [003] 1637.254685: fget_light <-do_sys_poll yum-updatesd-3111 [003] 1637.254686: pipe_poll <-do_sys_poll -# echo -1 > /debug/tracing/set_ftrace_pid -# cat /debug/tracing/trace |head +# echo -1 > set_ftrace_pid +# cat trace |head # tracer: function # # TASK-PID CPU# TIMESTAMP FUNCTION @@ -1216,6 +1222,51 @@ something like this simple program: #include <fcntl.h> #include <unistd.h> +#define _STR(x) #x +#define STR(x) _STR(x) +#define MAX_PATH 256 + +const char *find_debugfs(void) +{ + static char debugfs[MAX_PATH+1]; + static int debugfs_found; + char type[100]; + FILE *fp; + + if (debugfs_found) + return debugfs; + + if ((fp = fopen("/proc/mounts","r")) == NULL) { + perror("/proc/mounts"); + return NULL; + } + + while (fscanf(fp, "%*s %" + STR(MAX_PATH) + "s %99s %*s %*d %*d\n", + debugfs, type) == 2) { + if (strcmp(type, "debugfs") == 0) + break; + } + fclose(fp); + + if (strcmp(type, "debugfs") != 0) { + fprintf(stderr, "debugfs not mounted"); + return NULL; + } + + debugfs_found = 1; + + return debugfs; +} + +const char *tracing_file(const char *file_name) +{ + static char trace_file[MAX_PATH+1]; + snprintf(trace_file, MAX_PATH, "%s/%s", find_debugfs(), file_name); + return trace_file; +} + int main (int argc, char **argv) { if (argc < 1) @@ -1226,12 +1277,12 @@ int main (int argc, char **argv) char line[64]; int s; - ffd = open("/debug/tracing/current_tracer", O_WRONLY); + ffd = open(tracing_file("current_tracer"), O_WRONLY); if (ffd < 0) exit(-1); write(ffd, "nop", 3); - fd = open("/debug/tracing/set_ftrace_pid", O_WRONLY); + fd = open(tracing_file("set_ftrace_pid"), O_WRONLY); s = sprintf(line, "%d\n", getpid()); write(fd, line, s); @@ -1383,22 +1434,22 @@ want, depending on your needs. tracing_cpu_mask file) or you might sometimes see unordered function calls while cpu tracing switch. - hide: echo nofuncgraph-cpu > /debug/tracing/trace_options - show: echo funcgraph-cpu > /debug/tracing/trace_options + hide: echo nofuncgraph-cpu > trace_options + show: echo funcgraph-cpu > trace_options - The duration (function's time of execution) is displayed on the closing bracket line of a function or on the same line than the current function in case of a leaf one. It is default enabled. - hide: echo nofuncgraph-duration > /debug/tracing/trace_options - show: echo funcgraph-duration > /debug/tracing/trace_options + hide: echo nofuncgraph-duration > trace_options + show: echo funcgraph-duration > trace_options - The overhead field precedes the duration field in case of reached duration thresholds. - hide: echo nofuncgraph-overhead > /debug/tracing/trace_options - show: echo funcgraph-overhead > /debug/tracing/trace_options + hide: echo nofuncgraph-overhead > trace_options + show: echo funcgraph-overhead > trace_options depends on: funcgraph-duration ie: @@ -1427,8 +1478,8 @@ want, depending on your needs. - The task/pid field displays the thread cmdline and pid which executed the function. It is default disabled. - hide: echo nofuncgraph-proc > /debug/tracing/trace_options - show: echo funcgraph-proc > /debug/tracing/trace_options + hide: echo nofuncgraph-proc > trace_options + show: echo funcgraph-proc > trace_options ie: @@ -1451,8 +1502,8 @@ want, depending on your needs. system clock since it started. A snapshot of this time is given on each entry/exit of functions - hide: echo nofuncgraph-abstime > /debug/tracing/trace_options - show: echo funcgraph-abstime > /debug/tracing/trace_options + hide: echo nofuncgraph-abstime > trace_options + show: echo funcgraph-abstime > trace_options ie: @@ -1549,7 +1600,7 @@ listed in: available_filter_functions - # cat /debug/tracing/available_filter_functions + # cat available_filter_functions put_prev_task_idle kmem_cache_create pick_next_task_rt @@ -1561,12 +1612,12 @@ mutex_lock If I am only interested in sys_nanosleep and hrtimer_interrupt: # echo sys_nanosleep hrtimer_interrupt \ - > /debug/tracing/set_ftrace_filter - # echo ftrace > /debug/tracing/current_tracer - # echo 1 > /debug/tracing/tracing_enabled + > set_ftrace_filter + # echo ftrace > current_tracer + # echo 1 > tracing_enabled # usleep 1 - # echo 0 > /debug/tracing/tracing_enabled - # cat /debug/tracing/trace + # echo 0 > tracing_enabled + # cat trace # tracer: ftrace # # TASK-PID CPU# TIMESTAMP FUNCTION @@ -1577,7 +1628,7 @@ If I am only interested in sys_nanosleep and hrtimer_interrupt: To see which functions are being traced, you can cat the file: - # cat /debug/tracing/set_ftrace_filter + # cat set_ftrace_filter hrtimer_interrupt sys_nanosleep @@ -1597,7 +1648,7 @@ Note: It is better to use quotes to enclose the wild cards, otherwise the shell may expand the parameters into names of files in the local directory. - # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter + # echo 'hrtimer_*' > set_ftrace_filter Produces: @@ -1618,7 +1669,7 @@ Produces: Notice that we lost the sys_nanosleep. - # cat /debug/tracing/set_ftrace_filter + # cat set_ftrace_filter hrtimer_run_queues hrtimer_run_pending hrtimer_init @@ -1644,17 +1695,17 @@ To append to the filters, use '>>' To clear out a filter so that all functions will be recorded again: - # echo > /debug/tracing/set_ftrace_filter - # cat /debug/tracing/set_ftrace_filter + # echo > set_ftrace_filter + # cat set_ftrace_filter # Again, now we want to append. - # echo sys_nanosleep > /debug/tracing/set_ftrace_filter - # cat /debug/tracing/set_ftrace_filter + # echo sys_nanosleep > set_ftrace_filter + # cat set_ftrace_filter sys_nanosleep - # echo 'hrtimer_*' >> /debug/tracing/set_ftrace_filter - # cat /debug/tracing/set_ftrace_filter + # echo 'hrtimer_*' >> set_ftrace_filter + # cat set_ftrace_filter hrtimer_run_queues hrtimer_run_pending hrtimer_init @@ -1677,7 +1728,7 @@ hrtimer_init_sleeper The set_ftrace_notrace prevents those functions from being traced. - # echo '*preempt*' '*lock*' > /debug/tracing/set_ftrace_notrace + # echo '*preempt*' '*lock*' > set_ftrace_notrace Produces: @@ -1767,13 +1818,13 @@ the effect on the tracing is different. Every read from trace_pipe is consumed. This means that subsequent reads will be different. The trace is live. - # echo function > /debug/tracing/current_tracer - # cat /debug/tracing/trace_pipe > /tmp/trace.out & + # echo function > current_tracer + # cat trace_pipe > /tmp/trace.out & [1] 4153 - # echo 1 > /debug/tracing/tracing_enabled + # echo 1 > tracing_enabled # usleep 1 - # echo 0 > /debug/tracing/tracing_enabled - # cat /debug/tracing/trace + # echo 0 > tracing_enabled + # cat trace # tracer: function # # TASK-PID CPU# TIMESTAMP FUNCTION @@ -1809,7 +1860,7 @@ number listed is the number of entries that can be recorded per CPU. To know the full size, multiply the number of possible CPUS with the number of entries. - # cat /debug/tracing/buffer_size_kb + # cat buffer_size_kb 1408 (units kilobytes) Note, to modify this, you must have tracing completely disabled. @@ -1817,18 +1868,18 @@ To do that, echo "nop" into the current_tracer. If the current_tracer is not set to "nop", an EINVAL error will be returned. - # echo nop > /debug/tracing/current_tracer - # echo 10000 > /debug/tracing/buffer_size_kb - # cat /debug/tracing/buffer_size_kb + # echo nop > current_tracer + # echo 10000 > buffer_size_kb + # cat buffer_size_kb 10000 (units kilobytes) The number of pages which will be allocated is limited to a percentage of available memory. Allocating too much will produce an error. - # echo 1000000000000 > /debug/tracing/buffer_size_kb + # echo 1000000000000 > buffer_size_kb -bash: echo: write error: Cannot allocate memory - # cat /debug/tracing/buffer_size_kb + # cat buffer_size_kb 85 ----------- diff --git a/Documentation/trace/mmiotrace.txt b/Documentation/trace/mmiotrace.txt index 5731c67abc5..162effbfbde 100644 --- a/Documentation/trace/mmiotrace.txt +++ b/Documentation/trace/mmiotrace.txt @@ -32,41 +32,41 @@ is no way to automatically detect if you are losing events due to CPUs racing. Usage Quick Reference --------------------- -$ mount -t debugfs debugfs /debug -$ echo mmiotrace > /debug/tracing/current_tracer -$ cat /debug/tracing/trace_pipe > mydump.txt & +$ mount -t debugfs debugfs /sys/kernel/debug +$ echo mmiotrace > /sys/kernel/debug/tracing/current_tracer +$ cat /sys/kernel/debug/tracing/trace_pipe > mydump.txt & Start X or whatever. -$ echo "X is up" > /debug/tracing/trace_marker -$ echo nop > /debug/tracing/current_tracer +$ echo "X is up" > /sys/kernel/debug/tracing/trace_marker +$ echo nop > /sys/kernel/debug/tracing/current_tracer Check for lost events. Usage ----- -Make sure debugfs is mounted to /debug. If not, (requires root privileges) -$ mount -t debugfs debugfs /debug +Make sure debugfs is mounted to /sys/kernel/debug. If not, (requires root privileges) +$ mount -t debugfs debugfs /sys/kernel/debug Check that the driver you are about to trace is not loaded. Activate mmiotrace (requires root privileges): -$ echo mmiotrace > /debug/tracing/current_tracer +$ echo mmiotrace > /sys/kernel/debug/tracing/current_tracer Start storing the trace: -$ cat /debug/tracing/trace_pipe > mydump.txt & +$ cat /sys/kernel/debug/tracing/trace_pipe > mydump.txt & The 'cat' process should stay running (sleeping) in the background. Load the driver you want to trace and use it. Mmiotrace will only catch MMIO accesses to areas that are ioremapped while mmiotrace is active. During tracing you can place comments (markers) into the trace by -$ echo "X is up" > /debug/tracing/trace_marker +$ echo "X is up" > /sys/kernel/debug/tracing/trace_marker This makes it easier to see which part of the (huge) trace corresponds to which action. It is recommended to place descriptive markers about what you do. Shut down mmiotrace (requires root privileges): -$ echo nop > /debug/tracing/current_tracer +$ echo nop > /sys/kernel/debug/tracing/current_tracer The 'cat' process exits. If it does not, kill it by issuing 'fg' command and pressing ctrl+c. @@ -78,10 +78,10 @@ to view your kernel log and look for "mmiotrace has lost events" warning. If events were lost, the trace is incomplete. You should enlarge the buffers and try again. Buffers are enlarged by first seeing how large the current buffers are: -$ cat /debug/tracing/buffer_size_kb +$ cat /sys/kernel/debug/tracing/buffer_size_kb gives you a number. Approximately double this number and write it back, for instance: -$ echo 128000 > /debug/tracing/buffer_size_kb +$ echo 128000 > /sys/kernel/debug/tracing/buffer_size_kb Then start again from the top. If you are doing a trace for a driver project, e.g. Nouveau, you should also |