Set of configurations to emulate slower devices for some experiments. More...

Detailed Description

Set of configurations to emulate slower devices for some experiments.

For snapshot files and log files, we have an option to emulate slower devices. In some experiments, we use them to emulate NVM/SSD/etc on DRAM (RAMDisk). This is a POD.

Definition at line 36 of file device_emulation_options.hpp.

#include <device_emulation_options.hpp>

Inheritance diagram for foedus::fs::DeviceEmulationOptions:

[legend]

Collaboration diagram for foedus::fs::DeviceEmulationOptions:

[legend]

Public Member Functions
	DeviceEmulationOptions ()

ErrorStack	load (tinyxml2::XMLElement *element) override
	Reads the content of this object from the given XML element. More...

ErrorStack	save (tinyxml2::XMLElement *element) const override
	Writes the content of this object to the given XML element. More...

const char *	get_tag_name () const override
	Returns an XML tag name for this object as a root element. More...

void	assign (const foedus::externalize::Externalizable *other) override
	Polymorphic assign operator. More...

Public Member Functions inherited from foedus::externalize::Externalizable
ErrorStack	load_from_string (const std::string &xml)
	Load the content of this object from the given XML string. More...

void	save_to_stream (std::ostream *ptr) const
	Invokes save() and directs the resulting XML text to the given stream. More...

ErrorStack	load_from_file (const fs::Path &path)
	Load the content of this object from the specified XML file. More...

ErrorStack	save_to_file (const fs::Path &path) const
	Atomically and durably writes out this object to the specified XML file. More...

Public Attributes
bool	disable_direct_io_
	[Experiments] Whether to disable Direct I/O and use non-direct I/O instead. More...

bool	null_device_
	[Experiments] as if we write out to /dev/null. More...

uint32_t	emulated_seek_latency_cycles_
	[Experiments] additional CPU cycles to busy-wait for each seek. More...

uint32_t	emulated_read_kb_cycles_
	[Experiments] additional CPU cycles to busy-wait for each 1KB read. More...

uint32_t	emulated_write_kb_cycles_
	[Experiments] additional CPU cycles to busy-wait for each 1KB write. More...

Friends
std::ostream &	operator<< (std::ostream &o, const DeviceEmulationOptions &v)

Additional Inherited Members
Static Public Member Functions inherited from foedus::externalize::Externalizable
static ErrorStack	insert_comment (tinyxml2::XMLElement *element, const std::string &comment)

static ErrorStack	append_comment (tinyxml2::XMLElement *parent, const std::string &comment)

static ErrorStack	create_element (tinyxml2::XMLElement parent, const std::string &name, tinyxml2::XMLElement *out)

template<typename T >
static ErrorStack	add_element (tinyxml2::XMLElement *parent, const std::string &tag, const std::string &comment, T value)
	Only declaration in header. More...

template<uint MAXLEN, typename CHAR >
static ErrorStack	add_element (tinyxml2::XMLElement *parent, const std::string &tag, const std::string &comment, const assorted::FixedString< MAXLEN, CHAR > &value)

template<typename T >
static ErrorStack	add_element (tinyxml2::XMLElement *parent, const std::string &tag, const std::string &comment, const std::vector< T > &value)
	vector version More...

template<typename ENUM >
static ErrorStack	add_enum_element (tinyxml2::XMLElement *parent, const std::string &tag, const std::string &comment, ENUM value)
	enum version More...

static ErrorStack	add_child_element (tinyxml2::XMLElement *parent, const std::string &tag, const std::string &comment, const Externalizable &child)
	child Externalizable version More...

template<typename T >
static ErrorStack	get_element (tinyxml2::XMLElement parent, const std::string &tag, T out, bool optional=false, T value=0)
	Only declaration in header. More...

static ErrorStack	get_element (tinyxml2::XMLElement parent, const std::string &tag, std::string out, bool optional=false, const char *value="")
	string type is bit special. More...

template<uint MAXLEN, typename CHAR >
static ErrorStack	get_element (tinyxml2::XMLElement parent, const std::string &tag, assorted::FixedString< MAXLEN, CHAR > out, bool optional=false, const assorted::FixedString< MAXLEN, CHAR > &value=assorted::FixedString< MAXLEN, CHAR >())

template<typename ENUM >
static ErrorStack	get_enum_element (tinyxml2::XMLElement parent, const std::string &tag, ENUM out, bool optional=false, ENUM default_value=static_cast< ENUM >(0))
	enum version More...

template<typename T >
static ErrorStack	get_element (tinyxml2::XMLElement parent, const std::string &tag, std::vector< T > out, bool optional=false)
	vector version. More...

static ErrorStack	get_child_element (tinyxml2::XMLElement parent, const std::string &tag, Externalizable child, bool optional=false)
	child Externalizable version More...

Constructor & Destructor Documentation

foedus::fs::DeviceEmulationOptions::DeviceEmulationOptions ( )

inline

Definition at line 37 of file device_emulation_options.hpp.

References disable_direct_io_, emulated_read_kb_cycles_, emulated_seek_latency_cycles_, emulated_write_kb_cycles_, and null_device_.

                            {
     disable_direct_io_ = false;
     null_device_ = false;
     emulated_seek_latency_cycles_ = 0;
     emulated_read_kb_cycles_ = 0;
     emulated_write_kb_cycles_ = 0;
   }

Member Function Documentation

void foedus::fs::DeviceEmulationOptions::assign ( const foedus::externalize::Externalizable * other )

inlineoverridevirtual

Polymorphic assign operator.

This should invoke operator= of the derived class.

Parameters

[in] other assigned value. It must be dynamic-castable to the assignee class.

Implements foedus::externalize::Externalizable.

Definition at line 65 of file device_emulation_options.hpp.

const char* foedus::fs::DeviceEmulationOptions::get_tag_name ( ) const

inlineoverridevirtual

Returns an XML tag name for this object as a root element.

We might want to give a different name for same externalizable objects, so this is used only when it is the root element of xml.

Implements foedus::externalize::Externalizable.

Definition at line 65 of file device_emulation_options.hpp.

ErrorStack foedus::fs::DeviceEmulationOptions::load ( tinyxml2::XMLElement * element )

overridevirtual

Reads the content of this object from the given XML element.

Parameters

[in] element the XML element that represents this object

Expect errors due to missing-elements, out-of-range values, etc.

Implements foedus::externalize::Externalizable.

Definition at line 22 of file device_emulation_options.cpp.

References disable_direct_io_, emulated_read_kb_cycles_, emulated_seek_latency_cycles_, emulated_write_kb_cycles_, EXTERNALIZE_LOAD_ELEMENT, foedus::kRetOk, and null_device_.

                                                                    {
   EXTERNALIZE_LOAD_ELEMENT(element, disable_direct_io_);
   EXTERNALIZE_LOAD_ELEMENT(element, null_device_);
   EXTERNALIZE_LOAD_ELEMENT(element, emulated_seek_latency_cycles_);
   EXTERNALIZE_LOAD_ELEMENT(element, emulated_read_kb_cycles_);
   EXTERNALIZE_LOAD_ELEMENT(element, emulated_write_kb_cycles_);
   return kRetOk;
 }

ErrorStack foedus::fs::DeviceEmulationOptions::save ( tinyxml2::XMLElement * element ) const

overridevirtual

Writes the content of this object to the given XML element.

Parameters

[in] element the XML element that represents this object

Expect only out-of-memory error. We receive the XML element this object will represent, so this method does not determine the XML element name of itself. The parent object determines children's tag names because one parent object might have multiple child objects of the same type with different XML element name.

Implements foedus::externalize::Externalizable.

Definition at line 31 of file device_emulation_options.cpp.

References disable_direct_io_, emulated_read_kb_cycles_, emulated_seek_latency_cycles_, emulated_write_kb_cycles_, EXTERNALIZE_SAVE_ELEMENT, foedus::kRetOk, and null_device_.

                                                                          {
   EXTERNALIZE_SAVE_ELEMENT(element, disable_direct_io_,
     "Whether to disable Direct I/O and use non-direct I/O instead.");
   EXTERNALIZE_SAVE_ELEMENT(element, null_device_,
     "As if we write out to /dev/null. Used to measure performance w/o I/O.");
   EXTERNALIZE_SAVE_ELEMENT(element, emulated_seek_latency_cycles_,
     "additional CPU cycles to busy-wait for each seek. 0 (default) disables it.");
   EXTERNALIZE_SAVE_ELEMENT(element, emulated_read_kb_cycles_,
     "additional CPU cycles to busy-wait for each 1KB read. 0 (default) disables it."
     " For example, 4kb read is seek+scan*4 cycles, 1MB read is seek+scan*1000 cycles.");
   EXTERNALIZE_SAVE_ELEMENT(element, emulated_write_kb_cycles_,
     "additional CPU cycles to busy-wait for each 1KB write. 0 (default) disables it.");
   return kRetOk;
 }

Friends And Related Function Documentation

std::ostream& operator<<	(	std::ostream &	o,
		const DeviceEmulationOptions &	v
	)

friend

Definition at line 65 of file device_emulation_options.hpp.

Member Data Documentation

bool foedus::fs::DeviceEmulationOptions::disable_direct_io_

[Experiments] Whether to disable Direct I/O and use non-direct I/O instead.

Definition at line 46 of file device_emulation_options.hpp.

Referenced by DeviceEmulationOptions(), load(), foedus::fs::DirectIoFile::open(), foedus::fs::DirectIoFile::read_raw(), save(), and foedus::fs::DirectIoFile::write_raw().

uint32_t foedus::fs::DeviceEmulationOptions::emulated_read_kb_cycles_

[Experiments] additional CPU cycles to busy-wait for each 1KB read.

0 (default) disables it. For example, 4kb read is seek+read*4 cycles, 1MB read is seek+read*1024 cycles.

Definition at line 58 of file device_emulation_options.hpp.

Referenced by DeviceEmulationOptions(), load(), foedus::fs::DirectIoFile::read_raw(), and save().

uint32_t foedus::fs::DeviceEmulationOptions::emulated_seek_latency_cycles_

[Experiments] additional CPU cycles to busy-wait for each seek.

0 (default) disables it.

Definition at line 52 of file device_emulation_options.hpp.

Referenced by DeviceEmulationOptions(), load(), save(), and foedus::fs::DirectIoFile::seek().

uint32_t foedus::fs::DeviceEmulationOptions::emulated_write_kb_cycles_

[Experiments] additional CPU cycles to busy-wait for each 1KB write.

0 (default) disables it.

Definition at line 63 of file device_emulation_options.hpp.

Referenced by DeviceEmulationOptions(), load(), save(), and foedus::fs::DirectIoFile::write_raw().

bool foedus::fs::DeviceEmulationOptions::null_device_

[Experiments] as if we write out to /dev/null.

Used to measure performance w/o I/O

Definition at line 49 of file device_emulation_options.hpp.

Referenced by DeviceEmulationOptions(), load(), foedus::xct::XctManagerPimpl::precommit_xct_readwrite(), foedus::fs::DirectIoFile::read(), foedus::fs::DirectIoFile::read_raw(), save(), foedus::fs::DirectIoFile::seek(), foedus::fs::DirectIoFile::sync(), foedus::fs::DirectIoFile::truncate(), foedus::log::ThreadLogBuffer::wait_for_space(), and foedus::fs::DirectIoFile::write_raw().

The documentation for this struct was generated from the following files:

/home/shino/foedus_code/foedus-core/include/foedus/fs/device_emulation_options.hpp
/home/shino/foedus_code/foedus-core/src/foedus/fs/device_emulation_options.cpp

Detailed Description

Public Member Functions

Public Attributes

Friends

Additional Inherited Members

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation