diff options
Diffstat (limited to 'Documentation/trace')
| -rw-r--r-- | Documentation/trace/coresight/coresight.rst | 4 | ||||
| -rw-r--r-- | Documentation/trace/ftrace-uses.rst | 4 | ||||
| -rw-r--r-- | Documentation/trace/ftrace.rst | 38 | ||||
| -rw-r--r-- | Documentation/trace/kprobes.rst | 3 |
4 files changed, 45 insertions, 4 deletions
diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst index 826e59a698da..d4f93d6a2d63 100644 --- a/Documentation/trace/coresight/coresight.rst +++ b/Documentation/trace/coresight/coresight.rst @@ -624,6 +624,10 @@ They are also listed in the folder /sys/bus/event_source/devices/cs_etm/format/ * - timestamp - Session local version of the system wide setting: :ref:`ETMv4_MODE_TIMESTAMP <coresight-timestamp>` + * - cc_threshold + - Cycle count threshold value. If nothing is provided here or the provided value is 0, then the + default value i.e 0x100 will be used. If provided value is less than minimum cycles threshold + value, as indicated via TRCIDR3.CCITMIN, then the minimum value will be used instead. How to use the STM module ------------------------- diff --git a/Documentation/trace/ftrace-uses.rst b/Documentation/trace/ftrace-uses.rst index f7d98ae5b885..e198854ace79 100644 --- a/Documentation/trace/ftrace-uses.rst +++ b/Documentation/trace/ftrace-uses.rst @@ -182,7 +182,7 @@ FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED FTRACE_OPS_FL_RECURSION By default, it is expected that the callback can handle recursion. - But if the callback is not that worried about overehead, then + But if the callback is not that worried about overhead, then setting this bit will add the recursion protection around the callback by calling a helper function that will do the recursion protection and only call the callback if it did not recurse. @@ -190,7 +190,7 @@ FTRACE_OPS_FL_RECURSION Note, if this flag is not set, and recursion does occur, it could cause the system to crash, and possibly reboot via a triple fault. - Not, if this flag is set, then the callback will always be called + Note, if this flag is set, then the callback will always be called with preemption disabled. If it is not set, then it is possible (but not guaranteed) that the callback will be called in preemptable context. diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst index 23572f6697c0..7e7b8ec17934 100644 --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -180,6 +180,21 @@ of ftrace. Here is a list of some of the key files: Only active when the file contains a number greater than 0. (in microseconds) + buffer_percent: + + This is the watermark for how much the ring buffer needs to be filled + before a waiter is woken up. That is, if an application calls a + blocking read syscall on one of the per_cpu trace_pipe_raw files, it + will block until the given amount of data specified by buffer_percent + is in the ring buffer before it wakes the reader up. This also + controls how the splice system calls are blocked on this file:: + + 0 - means to wake up as soon as there is any data in the ring buffer. + 50 - means to wake up when roughly half of the ring buffer sub-buffers + are full. + 100 - means to block until the ring buffer is totally full and is + about to start overwriting the older data. + buffer_size_kb: This sets or displays the number of kilobytes each CPU @@ -203,6 +218,27 @@ of ftrace. Here is a list of some of the key files: This displays the total combined size of all the trace buffers. + buffer_subbuf_size_kb: + + This sets or displays the sub buffer size. The ring buffer is broken up + into several same size "sub buffers". An event can not be bigger than + the size of the sub buffer. Normally, the sub buffer is the size of the + architecture's page (4K on x86). The sub buffer also contains meta data + at the start which also limits the size of an event. That means when + the sub buffer is a page size, no event can be larger than the page + size minus the sub buffer meta data. + + Note, the buffer_subbuf_size_kb is a way for the user to specify the + minimum size of the subbuffer. The kernel may make it bigger due to the + implementation details, or simply fail the operation if the kernel can + not handle the request. + + Changing the sub buffer size allows for events to be larger than the + page size. + + Note: When changing the sub-buffer size, tracing is stopped and any + data in the ring buffer and the snapshot buffer will be discarded. + free_buffer: If a process is performing tracing, and the ring buffer should be @@ -2574,7 +2610,7 @@ want, depending on your needs. - The cpu number on which the function executed is default enabled. It is sometimes better to only trace one cpu (see - tracing_cpu_mask file) or you might sometimes see unordered + tracing_cpumask file) or you might sometimes see unordered function calls while cpu tracing switch. - hide: echo nofuncgraph-cpu > trace_options diff --git a/Documentation/trace/kprobes.rst b/Documentation/trace/kprobes.rst index f825970a1495..e1636e579c9c 100644 --- a/Documentation/trace/kprobes.rst +++ b/Documentation/trace/kprobes.rst @@ -4,7 +4,7 @@ Kernel Probes (Kprobes) :Author: Jim Keniston <jkenisto@us.ibm.com> :Author: Prasanna S Panchamukhi <prasanna.panchamukhi@gmail.com> -:Author: Masami Hiramatsu <mhiramat@redhat.com> +:Author: Masami Hiramatsu <mhiramat@kernel.org> .. CONTENTS @@ -321,6 +321,7 @@ architectures: - mips - s390 - parisc +- loongarch Configuring Kprobes =================== |