diff options
Diffstat (limited to 'Documentation/trace')
| -rw-r--r-- | Documentation/trace/coresight/coresight-cpu-debug.rst | 3 | ||||
| -rw-r--r-- | Documentation/trace/coresight/coresight-etm4x-reference.rst | 14 | ||||
| -rw-r--r-- | Documentation/trace/hisi-ptt.rst | 298 | ||||
| -rw-r--r-- | Documentation/trace/histogram.rst | 2 | ||||
| -rw-r--r-- | Documentation/trace/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/trace/kprobes.rst | 4 | ||||
| -rw-r--r-- | Documentation/trace/timerlat-tracer.rst | 2 |
7 files changed, 319 insertions, 5 deletions
diff --git a/Documentation/trace/coresight/coresight-cpu-debug.rst b/Documentation/trace/coresight/coresight-cpu-debug.rst index 993dd294b81b..836b35532667 100644 --- a/Documentation/trace/coresight/coresight-cpu-debug.rst +++ b/Documentation/trace/coresight/coresight-cpu-debug.rst @@ -117,7 +117,8 @@ divide into below cases: Device Tree Bindings -------------------- -See Documentation/devicetree/bindings/arm/coresight-cpu-debug.txt for details. +See Documentation/devicetree/bindings/arm/arm,coresight-cpu-debug.yaml for +details. How to use the module diff --git a/Documentation/trace/coresight/coresight-etm4x-reference.rst b/Documentation/trace/coresight/coresight-etm4x-reference.rst index fb7578fd9372..70e34b8c81c1 100644 --- a/Documentation/trace/coresight/coresight-etm4x-reference.rst +++ b/Documentation/trace/coresight/coresight-etm4x-reference.rst @@ -71,6 +71,20 @@ the ‘TRC’ prefix. ---- +:File: ``ts_source`` (ro) +:Trace Registers: None. +:Notes: + When FEAT_TRF is implemented, value of TRFCR_ELx.TS used for trace session. Otherwise -1 + indicates an unknown time source. Check trcidr0.tssize to see if a global timestamp is + available. + +:Example: + ``$> cat ts_source`` + + ``$> 1`` + +---- + :File: ``addr_idx`` (rw) :Trace Registers: None. :Notes: diff --git a/Documentation/trace/hisi-ptt.rst b/Documentation/trace/hisi-ptt.rst new file mode 100644 index 000000000000..4f87d8e21065 --- /dev/null +++ b/Documentation/trace/hisi-ptt.rst @@ -0,0 +1,298 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================== +HiSilicon PCIe Tune and Trace device +====================================== + +Introduction +============ + +HiSilicon PCIe tune and trace device (PTT) is a PCIe Root Complex +integrated Endpoint (RCiEP) device, providing the capability +to dynamically monitor and tune the PCIe link's events (tune), +and trace the TLP headers (trace). The two functions are independent, +but is recommended to use them together to analyze and enhance the +PCIe link's performance. + +On Kunpeng 930 SoC, the PCIe Root Complex is composed of several +PCIe cores. Each PCIe core includes several Root Ports and a PTT +RCiEP, like below. The PTT device is capable of tuning and +tracing the links of the PCIe core. +:: + + +--------------Core 0-------+ + | | [ PTT ] | + | | [Root Port]---[Endpoint] + | | [Root Port]---[Endpoint] + | | [Root Port]---[Endpoint] + Root Complex |------Core 1-------+ + | | [ PTT ] | + | | [Root Port]---[ Switch ]---[Endpoint] + | | [Root Port]---[Endpoint] `-[Endpoint] + | | [Root Port]---[Endpoint] + +---------------------------+ + +The PTT device driver registers one PMU device for each PTT device. +The name of each PTT device is composed of 'hisi_ptt' prefix with +the id of the SICL and the Core where it locates. The Kunpeng 930 +SoC encapsulates multiple CPU dies (SCCL, Super CPU Cluster) and +IO dies (SICL, Super I/O Cluster), where there's one PCIe Root +Complex for each SICL. +:: + + /sys/devices/hisi_ptt<sicl_id>_<core_id> + +Tune +==== + +PTT tune is designed for monitoring and adjusting PCIe link parameters (events). +Currently we support events in 2 classes. The scope of the events +covers the PCIe core to which the PTT device belongs. + +Each event is presented as a file under $(PTT PMU dir)/tune, and +a simple open/read/write/close cycle will be used to tune the event. +:: + + $ cd /sys/devices/hisi_ptt<sicl_id>_<core_id>/tune + $ ls + qos_tx_cpl qos_tx_np qos_tx_p + tx_path_rx_req_alloc_buf_level + tx_path_tx_req_alloc_buf_level + $ cat qos_tx_dp + 1 + $ echo 2 > qos_tx_dp + $ cat qos_tx_dp + 2 + +Current value (numerical value) of the event can be simply read +from the file, and the desired value written to the file to tune. + +1. Tx Path QoS Control +------------------------ + +The following files are provided to tune the QoS of the tx path of +the PCIe core. + +- qos_tx_cpl: weight of Tx completion TLPs +- qos_tx_np: weight of Tx non-posted TLPs +- qos_tx_p: weight of Tx posted TLPs + +The weight influences the proportion of certain packets on the PCIe link. +For example, for the storage scenario, increase the proportion +of the completion packets on the link to enhance the performance as +more completions are consumed. + +The available tune data of these events is [0, 1, 2]. +Writing a negative value will return an error, and out of range +values will be converted to 2. Note that the event value just +indicates a probable level, but is not precise. + +2. Tx Path Buffer Control +------------------------- + +Following files are provided to tune the buffer of tx path of the PCIe core. + +- rx_alloc_buf_level: watermark of Rx requested +- tx_alloc_buf_level: watermark of Tx requested + +These events influence the watermark of the buffer allocated for each +type. Rx means the inbound while Tx means outbound. The packets will +be stored in the buffer first and then transmitted either when the +watermark reached or when timed out. For a busy direction, you should +increase the related buffer watermark to avoid frequently posting and +thus enhance the performance. In most cases just keep the default value. + +The available tune data of above events is [0, 1, 2]. +Writing a negative value will return an error, and out of range +values will be converted to 2. Note that the event value just +indicates a probable level, but is not precise. + +Trace +===== + +PTT trace is designed for dumping the TLP headers to the memory, which +can be used to analyze the transactions and usage condition of the PCIe +Link. You can choose to filter the traced headers by either Requester ID, +or those downstream of a set of Root Ports on the same core of the PTT +device. It's also supported to trace the headers of certain type and of +certain direction. + +You can use the perf command `perf record` to set the parameters, start +trace and get the data. It's also supported to decode the trace +data with `perf report`. The control parameters for trace is inputted +as event code for each events, which will be further illustrated later. +An example usage is like +:: + + $ perf record -e hisi_ptt0_2/filter=0x80001,type=1,direction=1, + format=1/ -- sleep 5 + +This will trace the TLP headers downstream root port 0000:00:10.1 (event +code for event 'filter' is 0x80001) with type of posted TLP requests, +direction of inbound and traced data format of 8DW. + +1. Filter +--------- + +The TLP headers to trace can be filtered by the Root Ports or the Requester ID +of the Endpoint, which are located on the same core of the PTT device. You can +set the filter by specifying the `filter` parameter which is required to start +the trace. The parameter value is 20 bit. Bit 19 indicates the filter type. +1 for Root Port filter and 0 for Requester filter. Bit[15:0] indicates the +filter value. The value for a Root Port is a mask of the core port id which is +calculated from its PCI Slot ID as (slotid & 7) * 2. The value for a Requester +is the Requester ID (Device ID of the PCIe function). Bit[18:16] is currently +reserved for extension. + +For example, if the desired filter is Endpoint function 0000:01:00.1 the filter +value will be 0x00101. If the desired filter is Root Port 0000:00:10.0 then +then filter value is calculated as 0x80001. + +Note that multiple Root Ports can be specified at one time, but only one +Endpoint function can be specified in one trace. Specifying both Root Port +and function at the same time is not supported. Driver maintains a list of +available filters and will check the invalid inputs. + +Currently the available filters are detected in driver's probe. If the supported +devices are removed/added after probe, you may need to reload the driver to update +the filters. + +2. Type +------- + +You can trace the TLP headers of certain types by specifying the `type` +parameter, which is required to start the trace. The parameter value is +8 bit. Current supported types and related values are shown below: + +- 8'b00000001: posted requests (P) +- 8'b00000010: non-posted requests (NP) +- 8'b00000100: completions (CPL) + +You can specify multiple types when tracing inbound TLP headers, but can only +specify one when tracing outbound TLP headers. + +3. Direction +------------ + +You can trace the TLP headers from certain direction, which is relative +to the Root Port or the PCIe core, by specifying the `direction` parameter. +This is optional and the default parameter is inbound. The parameter value +is 4 bit. When the desired format is 4DW, directions and related values +supported are shown below: + +- 4'b0000: inbound TLPs (P, NP, CPL) +- 4'b0001: outbound TLPs (P, NP, CPL) +- 4'b0010: outbound TLPs (P, NP, CPL) and inbound TLPs (P, NP, CPL B) +- 4'b0011: outbound TLPs (P, NP, CPL) and inbound TLPs (CPL A) + +When the desired format is 8DW, directions and related values supported are +shown below: + +- 4'b0000: reserved +- 4'b0001: outbound TLPs (P, NP, CPL) +- 4'b0010: inbound TLPs (P, NP, CPL B) +- 4'b0011: inbound TLPs (CPL A) + +Inbound completions are classified into two types: + +- completion A (CPL A): completion of CHI/DMA/Native non-posted requests, except for CPL B +- completion B (CPL B): completion of DMA remote2local and P2P non-posted requests + +4. Format +-------------- + +You can change the format of the traced TLP headers by specifying the +`format` parameter. The default format is 4DW. The parameter value is 4 bit. +Current supported formats and related values are shown below: + +- 4'b0000: 4DW length per TLP header +- 4'b0001: 8DW length per TLP header + +The traced TLP header format is different from the PCIe standard. + +When using the 8DW data format, the entire TLP header is logged +(Header DW0-3 shown below). For example, the TLP header for Memory +Reads with 64-bit addresses is shown in PCIe r5.0, Figure 2-17; +the header for Configuration Requests is shown in Figure 2.20, etc. + +In addition, 8DW trace buffer entries contain a timestamp and +possibly a prefix for a PASID TLP prefix (see Figure 6-20, PCIe r5.0). +Otherwise this field will be all 0. + +The bit[31:11] of DW0 is always 0x1fffff, which can be +used to distinguish the data format. 8DW format is like +:: + + bits [ 31:11 ][ 10:0 ] + |---------------------------------------|-------------------| + DW0 [ 0x1fffff ][ Reserved (0x7ff) ] + DW1 [ Prefix ] + DW2 [ Header DW0 ] + DW3 [ Header DW1 ] + DW4 [ Header DW2 ] + DW5 [ Header DW3 ] + DW6 [ Reserved (0x0) ] + DW7 [ Time ] + +When using the 4DW data format, DW0 of the trace buffer entry +contains selected fields of DW0 of the TLP, together with a +timestamp. DW1-DW3 of the trace buffer entry contain DW1-DW3 +directly from the TLP header. + +4DW format is like +:: + + bits [31:30] [ 29:25 ][24][23][22][21][ 20:11 ][ 10:0 ] + |-----|---------|---|---|---|---|-------------|-------------| + DW0 [ Fmt ][ Type ][T9][T8][TH][SO][ Length ][ Time ] + DW1 [ Header DW1 ] + DW2 [ Header DW2 ] + DW3 [ Header DW3 ] + +5. Memory Management +-------------------- + +The traced TLP headers will be written to the memory allocated +by the driver. The hardware accepts 4 DMA address with same size, +and writes the buffer sequentially like below. If DMA addr 3 is +finished and the trace is still on, it will return to addr 0. +:: + + +->[DMA addr 0]->[DMA addr 1]->[DMA addr 2]->[DMA addr 3]-+ + +---------------------------------------------------------+ + +Driver will allocate each DMA buffer of 4MiB. The finished buffer +will be copied to the perf AUX buffer allocated by the perf core. +Once the AUX buffer is full while the trace is still on, driver +will commit the AUX buffer first and then apply for a new one with +the same size. The size of AUX buffer is default to 16MiB. User can +adjust the size by specifying the `-m` parameter of the perf command. + +6. Decoding +----------- + +You can decode the traced data with `perf report -D` command (currently +only support to dump the raw trace data). The traced data will be decoded +according to the format described previously (take 8DW as an example): +:: + + [...perf headers and other information] + . ... HISI PTT data: size 4194304 bytes + . 00000000: 00 00 00 00 Prefix + . 00000004: 01 00 00 60 Header DW0 + . 00000008: 0f 1e 00 01 Header DW1 + . 0000000c: 04 00 00 00 Header DW2 + . 00000010: 40 00 81 02 Header DW3 + . 00000014: 33 c0 04 00 Time + . 00000020: 00 00 00 00 Prefix + . 00000024: 01 00 00 60 Header DW0 + . 00000028: 0f 1e 00 01 Header DW1 + . 0000002c: 04 00 00 00 Header DW2 + . 00000030: 40 00 81 02 Header DW3 + . 00000034: 02 00 00 00 Time + . 00000040: 00 00 00 00 Prefix + . 00000044: 01 00 00 60 Header DW0 + . 00000048: 0f 1e 00 01 Header DW1 + . 0000004c: 04 00 00 00 Header DW2 + . 00000050: 40 00 81 02 Header DW3 + [...] diff --git a/Documentation/trace/histogram.rst b/Documentation/trace/histogram.rst index 859fd1b76c63..c1b685a38f6b 100644 --- a/Documentation/trace/histogram.rst +++ b/Documentation/trace/histogram.rst @@ -412,7 +412,7 @@ Extended error information Because the default sort key above is 'hitcount', the above shows a the list of call_sites by increasing hitcount, so that at the bottom we see the functions that made the most kmalloc calls during the - run. If instead we we wanted to see the top kmalloc callers in + run. If instead we wanted to see the top kmalloc callers in terms of the number of bytes requested rather than the number of calls, and we wanted the top caller to appear at the top, we can use the 'sort' parameter, along with the 'descending' modifier:: diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst index 2d73e8697523..ea25a9220f92 100644 --- a/Documentation/trace/index.rst +++ b/Documentation/trace/index.rst @@ -33,3 +33,4 @@ Linux Tracing Technologies coresight/index user_events rv/index + hisi-ptt diff --git a/Documentation/trace/kprobes.rst b/Documentation/trace/kprobes.rst index f318bceda1e6..48cf778a2468 100644 --- a/Documentation/trace/kprobes.rst +++ b/Documentation/trace/kprobes.rst @@ -328,8 +328,8 @@ Configuring Kprobes =================== When configuring the kernel using make menuconfig/xconfig/oldconfig, -ensure that CONFIG_KPROBES is set to "y". Under "General setup", look -for "Kprobes". +ensure that CONFIG_KPROBES is set to "y", look for "Kprobes" under +"General architecture-dependent options". So that you can load and unload Kprobes-based instrumentation modules, make sure "Loadable module support" (CONFIG_MODULES) and "Module diff --git a/Documentation/trace/timerlat-tracer.rst b/Documentation/trace/timerlat-tracer.rst index d643c95c01eb..db17df312bc8 100644 --- a/Documentation/trace/timerlat-tracer.rst +++ b/Documentation/trace/timerlat-tracer.rst @@ -20,7 +20,7 @@ For example:: [root@f32 ~]# cd /sys/kernel/tracing/ [root@f32 tracing]# echo timerlat > current_tracer -It is possible to follow the trace by reading the trace trace file:: +It is possible to follow the trace by reading the trace file:: [root@f32 tracing]# cat trace # tracer: timerlat |