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authorLinus Torvalds <torvalds@linux-foundation.org>2013-11-20 22:20:24 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-20 22:20:24 +0100
commite6d69a60b77a6ea8d5f9d41765c7571bb8d45531 (patch)
tree4ea3fe7c49a864da2ce7ffb51a703661826dc15d /Documentation/dmatest.txt
parentMerge branch 'for-linus' of git://git.kernel.dk/linux-block (diff)
parentMerge commit 'dmaengine-3.13-v2' of git://git.kernel.org/pub/scm/linux/kernel... (diff)
downloadlinux-e6d69a60b77a6ea8d5f9d41765c7571bb8d45531.tar.xz
linux-e6d69a60b77a6ea8d5f9d41765c7571bb8d45531.zip
Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma
Pull slave-dmaengine changes from Vinod Koul: "This brings for slave dmaengine: - Change dma notification flag to DMA_COMPLETE from DMA_SUCCESS as dmaengine can only transfer and not verify validaty of dma transfers - Bunch of fixes across drivers: - cppi41 driver fixes from Daniel - 8 channel freescale dma engine support and updated bindings from Hongbo - msx-dma fixes and cleanup by Markus - DMAengine updates from Dan: - Bartlomiej and Dan finalized a rework of the dma address unmap implementation. - In the course of testing 1/ a collection of enhancements to dmatest fell out. Notably basic performance statistics, and fixed / enhanced test control through new module parameters 'run', 'wait', 'noverify', and 'verbose'. Thanks to Andriy and Linus [Walleij] for their review. - Testing the raid related corner cases of 1/ triggered bugs in the recently added 16-source operation support in the ioatdma driver. - Some minor fixes / cleanups to mv_xor and ioatdma" * 'next' of git://git.infradead.org/users/vkoul/slave-dma: (99 commits) dma: mv_xor: Fix mis-usage of mmio 'base' and 'high_base' registers dma: mv_xor: Remove unneeded NULL address check ioat: fix ioat3_irq_reinit ioat: kill msix_single_vector support raid6test: add new corner case for ioatdma driver ioatdma: clean up sed pool kmem_cache ioatdma: fix selection of 16 vs 8 source path ioatdma: fix sed pool selection ioatdma: Fix bug in selftest after removal of DMA_MEMSET. dmatest: verbose mode dmatest: convert to dmaengine_unmap_data dmatest: add a 'wait' parameter dmatest: add basic performance metrics dmatest: add support for skipping verification and random data setup dmatest: use pseudo random numbers dmatest: support xor-only, or pq-only channels in tests dmatest: restore ability to start test at module load and init dmatest: cleanup redundant "dmatest: " prefixes dmatest: replace stored results mechanism, with uniform messages Revert "dmatest: append verify result to results" ...
Diffstat (limited to 'Documentation/dmatest.txt')
-rw-r--r--Documentation/dmatest.txt72
1 files changed, 41 insertions, 31 deletions
diff --git a/Documentation/dmatest.txt b/Documentation/dmatest.txt
index a2b5663eae26..dd77a81bdb80 100644
--- a/Documentation/dmatest.txt
+++ b/Documentation/dmatest.txt
@@ -15,39 +15,48 @@ be built as module or inside kernel. Let's consider those cases.
Part 2 - When dmatest is built as a module...
-After mounting debugfs and loading the module, the /sys/kernel/debug/dmatest
-folder with nodes will be created. There are two important files located. First
-is the 'run' node that controls run and stop phases of the test, and the second
-one, 'results', is used to get the test case results.
-
-Note that in this case test will not run on load automatically.
-
Example of usage:
+ % modprobe dmatest channel=dma0chan0 timeout=2000 iterations=1 run=1
+
+...or:
+ % modprobe dmatest
% echo dma0chan0 > /sys/module/dmatest/parameters/channel
% echo 2000 > /sys/module/dmatest/parameters/timeout
% echo 1 > /sys/module/dmatest/parameters/iterations
- % echo 1 > /sys/kernel/debug/dmatest/run
+ % echo 1 > /sys/module/dmatest/parameters/run
+
+...or on the kernel command line:
+
+ dmatest.channel=dma0chan0 dmatest.timeout=2000 dmatest.iterations=1 dmatest.run=1
Hint: available channel list could be extracted by running the following
command:
% ls -1 /sys/class/dma/
-After a while you will start to get messages about current status or error like
-in the original code.
+Once started a message like "dmatest: Started 1 threads using dma0chan0" is
+emitted. After that only test failure messages are reported until the test
+stops.
Note that running a new test will not stop any in progress test.
-The following command should return actual state of the test.
- % cat /sys/kernel/debug/dmatest/run
-
-To wait for test done the user may perform a busy loop that checks the state.
-
- % while [ $(cat /sys/kernel/debug/dmatest/run) = "Y" ]
- > do
- > echo -n "."
- > sleep 1
- > done
- > echo
+The following command returns the state of the test.
+ % cat /sys/module/dmatest/parameters/run
+
+To wait for test completion userpace can poll 'run' until it is false, or use
+the wait parameter. Specifying 'wait=1' when loading the module causes module
+initialization to pause until a test run has completed, while reading
+/sys/module/dmatest/parameters/wait waits for any running test to complete
+before returning. For example, the following scripts wait for 42 tests
+to complete before exiting. Note that if 'iterations' is set to 'infinite' then
+waiting is disabled.
+
+Example:
+ % modprobe dmatest run=1 iterations=42 wait=1
+ % modprobe -r dmatest
+...or:
+ % modprobe dmatest run=1 iterations=42
+ % cat /sys/module/dmatest/parameters/wait
+ % modprobe -r dmatest
Part 3 - When built-in in the kernel...
@@ -62,21 +71,22 @@ case. You always could check them at run-time by running
Part 4 - Gathering the test results
-The module provides a storage for the test results in the memory. The gathered
-data could be used after test is done.
+Test results are printed to the kernel log buffer with the format:
-The special file 'results' in the debugfs represents gathered data of the in
-progress test. The messages collected are printed to the kernel log as well.
+"dmatest: result <channel>: <test id>: '<error msg>' with src_off=<val> dst_off=<val> len=<val> (<err code>)"
Example of output:
- % cat /sys/kernel/debug/dmatest/results
- dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0)
+ % dmesg | tail -n 1
+ dmatest: result dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0)
The message format is unified across the different types of errors. A number in
the parens represents additional information, e.g. error code, error counter,
-or status.
+or status. A test thread also emits a summary line at completion listing the
+number of tests executed, number that failed, and a result code.
-Comparison between buffers is stored to the dedicated structure.
+Example:
+ % dmesg | tail -n 1
+ dmatest: dma0chan0-copy0: summary 1 test, 0 failures 1000 iops 100000 KB/s (0)
-Note that the verify result is now accessible only via file 'results' in the
-debugfs.
+The details of a data miscompare error are also emitted, but do not follow the
+above format.