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-rw-r--r--Documentation/RCU/torture.txt34
1 files changed, 24 insertions, 10 deletions
diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt
index e4c38152f7f7..a4948591607d 100644
--- a/Documentation/RCU/torture.txt
+++ b/Documentation/RCU/torture.txt
@@ -7,7 +7,7 @@ The CONFIG_RCU_TORTURE_TEST config option is available for all RCU
7implementations. It creates an rcutorture kernel module that can 7implementations. It creates an rcutorture kernel module that can
8be loaded to run a torture test. The test periodically outputs 8be loaded to run a torture test. The test periodically outputs
9status messages via printk(), which can be examined via the dmesg 9status messages via printk(), which can be examined via the dmesg
10command (perhaps grepping for "rcutorture"). The test is started 10command (perhaps grepping for "torture"). The test is started
11when the module is loaded, and stops when the module is unloaded. 11when the module is loaded, and stops when the module is unloaded.
12 12
13However, actually setting this config option to "y" results in the system 13However, actually setting this config option to "y" results in the system
@@ -35,6 +35,19 @@ stat_interval The number of seconds between output of torture
35 be printed -only- when the module is unloaded, and this 35 be printed -only- when the module is unloaded, and this
36 is the default. 36 is the default.
37 37
38shuffle_interval
39 The number of seconds to keep the test threads affinitied
40 to a particular subset of the CPUs. Used in conjunction
41 with test_no_idle_hz.
42
43test_no_idle_hz Whether or not to test the ability of RCU to operate in
44 a kernel that disables the scheduling-clock interrupt to
45 idle CPUs. Boolean parameter, "1" to test, "0" otherwise.
46
47torture_type The type of RCU to test: "rcu" for the rcu_read_lock()
48 API, "rcu_bh" for the rcu_read_lock_bh() API, and "srcu"
49 for the "srcu_read_lock()" API.
50
38verbose Enable debug printk()s. Default is disabled. 51verbose Enable debug printk()s. Default is disabled.
39 52
40 53
@@ -42,14 +55,14 @@ OUTPUT
42 55
43The statistics output is as follows: 56The statistics output is as follows:
44 57
45 rcutorture: --- Start of test: nreaders=16 stat_interval=0 verbose=0 58 rcu-torture: --- Start of test: nreaders=16 stat_interval=0 verbose=0
46 rcutorture: rtc: 0000000000000000 ver: 1916 tfle: 0 rta: 1916 rtaf: 0 rtf: 1915 59 rcu-torture: rtc: 0000000000000000 ver: 1916 tfle: 0 rta: 1916 rtaf: 0 rtf: 1915
47 rcutorture: Reader Pipe: 1466408 9747 0 0 0 0 0 0 0 0 0 60 rcu-torture: Reader Pipe: 1466408 9747 0 0 0 0 0 0 0 0 0
48 rcutorture: Reader Batch: 1464477 11678 0 0 0 0 0 0 0 0 61 rcu-torture: Reader Batch: 1464477 11678 0 0 0 0 0 0 0 0
49 rcutorture: Free-Block Circulation: 1915 1915 1915 1915 1915 1915 1915 1915 1915 1915 0 62 rcu-torture: Free-Block Circulation: 1915 1915 1915 1915 1915 1915 1915 1915 1915 1915 0
50 rcutorture: --- End of test 63 rcu-torture: --- End of test
51 64
52The command "dmesg | grep rcutorture:" will extract this information on 65The command "dmesg | grep torture:" will extract this information on
53most systems. On more esoteric configurations, it may be necessary to 66most systems. On more esoteric configurations, it may be necessary to
54use other commands to access the output of the printk()s used by 67use other commands to access the output of the printk()s used by
55the RCU torture test. The printk()s use KERN_ALERT, so they should 68the RCU torture test. The printk()s use KERN_ALERT, so they should
@@ -115,8 +128,9 @@ The following script may be used to torture RCU:
115 modprobe rcutorture 128 modprobe rcutorture
116 sleep 100 129 sleep 100
117 rmmod rcutorture 130 rmmod rcutorture
118 dmesg | grep rcutorture: 131 dmesg | grep torture:
119 132
120The output can be manually inspected for the error flag of "!!!". 133The output can be manually inspected for the error flag of "!!!".
121One could of course create a more elaborate script that automatically 134One could of course create a more elaborate script that automatically
122checked for such errors. 135checked for such errors. The "rmmod" command forces a "SUCCESS" or
136"FAILURE" indication to be printk()ed.