wok diff memtester/description.txt @ rev 19566
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author | Richard Dunbar <mojo@slitaz.org> |
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date | Tue Dec 20 01:18:30 2016 -0500 (2016-12-20) |
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1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 1.2 +++ b/memtester/description.txt Tue Dec 20 01:18:30 2016 -0500 1.3 @@ -0,0 +1,43 @@ 1.4 +memtester is a utility for testing the memory subsystem in a computer to 1.5 +determine if it is faulty. 1.6 + 1.7 +Usage is simple for the basic case. As root, run the resulting memtester binary 1.8 +with the following commandline: 1.9 + 1.10 + memtester <memory> [runs] 1.11 + 1.12 +where `<memory>` is the amount of memory to test, in megabytes by default. You 1.13 +can optionally include a suffix of B, K, M, or G (for bytes, kilobytes, 1.14 +megabytes, and gigabytes respectively). 1.15 + 1.16 +`[runs]` is an optional limit to the number of runs through all tests. 1.17 + 1.18 +An optional `-p physaddr` argument available to cause memtester to test memory 1.19 +starting at a specific physical memory address (by mmap(2)ing a device file 1.20 +representing physical memory (/dev/mem by default, but can be specified with the 1.21 +`-d device` option) starting at an offset of `physaddr`, which is given in hex). 1.22 + 1.23 +Note: the memory specified will be overwritten during testing; you therefore 1.24 +*cannot* specify a region belonging to the kernel or other applications without 1.25 +causing the other process or entire system to crash). If you use this option, it 1.26 +is up to you to ensure the specified memory is safe to overwrite. That makes 1.27 +this option mostly of use for testing memory-mapped I/O devices and similar. 1.28 +Thanks to Allon Stern for the idea behind this feature. For example, if you want 1.29 +to test a bank of RAM or device which is 64kbytes in size and starts at physical 1.30 +address 0x0C0000 through the normal /dev/mem, you would run memtester as 1.31 +follows: 1.32 + 1.33 + memtester -p 0x0c0000 64k [runs] 1.34 + 1.35 +If instead that device presented its memory as /dev/foodev at offset 0, you 1.36 +would run memtester instead as follows: 1.37 + 1.38 + memtester -p 0 -d /dev/foodev 64k [runs] 1.39 + 1.40 +Note that the `-d` option can only be specified in combination with `-p`. 1.41 + 1.42 +memtester must run as user root so that it can lock its pages into memory. If 1.43 +memtester fails to lock its pages, it will issue a warning and continue 1.44 +regardless. Testing without the memory being locked is generally very slow and 1.45 +not particularly accurate, as you'll end up testing the same memory over and 1.46 +over as the system swaps the larger region.