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Stress options allow developers testing Open vSwitch to trigger behavior that otherwise would occur only in corner cases. Developers and testers can thereby more easily discover bugs that would otherwise manifest only rarely or nondeterministically. Stress options may cause surprising behavior even when they do not actually reveal bugs, so they should only be enabled as part of testing Open vSwitch. This commit implements the framework and adds a few example stress options. This commit started from code written by Andrew Lambeth. Suggested-by: Henrik Amren <henrik@nicira.com> CC: Andrew Lambeth <wal@nicira.com>
93 lines
3.7 KiB
C
93 lines
3.7 KiB
C
/*
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* Copyright (c) 2010 Nicira Networks.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef STRESS_H
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#define STRESS_H 1
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#include <stdbool.h>
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struct stress_option {
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/* Properties. */
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char *name; /* Short identifier string */
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char *description; /* Description of what the option stresses. */
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unsigned int recommended; /* Recommended period. */
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unsigned int min; /* Minimum period that can be set. */
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unsigned int max; /* Maximum period that can be set. */
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unsigned int def; /* Default value. */
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/* Configuration. */
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unsigned int period; /* Desired period for firing, 0 to disable. */
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bool random; /* Fire randomly or exactly at period? */
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/* State. */
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unsigned int counter; /* Number of hits before next firing. */
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unsigned long long int hits; /* Hits since last reset. */
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};
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/* Creates and initializes a global instance of a stress option.
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*
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* NAME is a single word descriptive identifier for the option. This is the
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* token to pass in to the STRESS() macro at the sites where exectution is to
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* be controlled by the option.
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*
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* DESCRIPTION is a quoted string that should describe to a person unfamiliar
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* with the detailed internals of the code what behavior the option affects.
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*
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* RECOMMENDED is a suggested value for a person unfamiliar with the internals.
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* It should put reasonable stress on the system without crippling it.
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*
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* MIN and MAX are the minimum and maximum values allowed for the option.
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*
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* DEFAULT is the default value for the option. Specify 0 to disable the
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* option by default, which should be the usual choice. But some options can
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* be left on at low levels without noticable impact to the end user. An
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* example would be failing to allocate a buffer for every 100000th packet
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* processed by the system.
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*/
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#if USE_LINKER_SECTIONS
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#define STRESS_OPTION(NAME, DESCRIPTION, RECOMMENDED, MIN, MAX, DEFAULT) \
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STRESS_OPTION__(NAME, DESCRIPTION, RECOMMENDED, MIN, MAX, DEFAULT); \
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struct stress_option *stress_option_ptr_##NAME \
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__attribute__((section("stress_options"))) = &stress_##NAME
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#else
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#define STRESS_OPTION(NAME, DESCRIPTION, RECOMMENDED, MIN, MAX, DEFAULT) \
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extern struct stress_option stress_##NAME
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#endif
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/* Yields true if stress option NAME should be triggered,
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* false otherwise. */
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#define STRESS(NAME) stress_sample__(&stress_##NAME)
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void stress_init_command(void);
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/* Implementation details. */
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#define STRESS_OPTION__(NAME, DESCRIPTION, RECOMMENDED, MIN, MAX, DEFAULT) \
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struct stress_option stress_##NAME = \
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{ #NAME, DESCRIPTION, RECOMMENDED, MIN, MAX, DEFAULT, \
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DEFAULT ? DEFAULT : 0, /* period */ \
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false, /* random */ \
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UINT_MAX, /* counter */ \
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0 } /* hits */
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bool stress_sample_slowpath__(struct stress_option *);
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static inline bool stress_sample__(struct stress_option *option)
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{
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return --option->counter == 0 && stress_sample_slowpath__(option);
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}
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#endif /* STRESS_H */
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