thin-provisioning-tools/base/io_generator.cc
Ming-Hung Tsai 7ed013fcab [io_generator] Rename offset_generator classes, and fix bugs
- Rename the classes for general-purpose usage
- Fix duplicated sequential number generation while wrap around
- Enable unaligned random number generation
2020-07-25 17:20:59 +08:00

267 lines
6.3 KiB
C++

#include "base/io_generator.h"
#include "persistent-data/run_set.h"
#include <stdexcept>
#include <cstdlib>
#include <cstring>
using namespace base;
//----------------------------------------------------------------
namespace {
std::pair<char const*, io_pattern::pattern> patterns[] = {
{"read", io_pattern::READ},
{"write", io_pattern::WRITE},
{"trim", io_pattern::TRIM},
{"readwrite", io_pattern::READ_WRITE},
{"trimwrite", io_pattern::TRIM_WRITE},
{"randread", io_pattern::RAND_READ},
{"randwrite", io_pattern::RAND_WRITE},
{"randtrim", io_pattern::RAND_TRIM},
{"randrw", io_pattern::RAND_RW},
{"randtw", io_pattern::RAND_TW}
};
unsigned const nr_patterns = sizeof(patterns) / sizeof(patterns[0]);
//--------------------------------
class sequence_generator {
public:
typedef std::shared_ptr<sequence_generator> ptr;
virtual uint64_t next() = 0;
};
// - The maximum generated value is not greater than (begin+size)
// - The generated values are not aligned to the step, if the begin
// value is not aligned.
class forward_sequence_generator: public sequence_generator {
public:
forward_sequence_generator(uint64_t begin,
uint64_t size,
uint64_t step)
: begin_(begin),
end_(begin + (size / step) * step),
step_(step),
current_(begin) {
if (size < step)
throw std::runtime_error("size must be greater than the step");
}
uint64_t next() {
uint64_t r = current_;
current_ += step_;
if (current_ >= end_) {
current_ = begin_;
}
return r;
}
private:
uint64_t begin_;
uint64_t end_;
uint64_t step_;
uint64_t current_;
};
// - The maximum generated value is not greater than (begin+size)
// - The generated values are not aligned to the step, if the begin
// value is not aligned.
class random_sequence_generator: public sequence_generator {
public:
// TODO: load random seeds
random_sequence_generator(uint64_t begin,
uint64_t size,
uint64_t step)
: begin_(begin),
nr_steps_(size / step),
step_(step),
nr_generated_(0) {
}
uint64_t next() {
uint64_t step_idx;
bool found = true;
while (found) {
step_idx = std::rand() % nr_steps_;
found = rand_map_.member(step_idx);
}
rand_map_.add(step_idx);
++nr_generated_;
// wrap-around
if (nr_generated_ == nr_steps_) {
rand_map_.clear();
nr_generated_ = 0;
}
return begin_ + step_idx * step_;
}
private:
uint64_t begin_;
uint64_t nr_steps_;
uint64_t step_;
base::run_set<uint64_t> rand_map_;
uint64_t nr_generated_;
};
//--------------------------------
class op_generator {
public:
typedef std::shared_ptr<op_generator> ptr;
op_generator(base::req_op op1)
: op1_(op1), op2_(op1), op1_pct_(100) {
}
op_generator(base::req_op op1,
base::req_op op2,
unsigned op1_pct)
: op1_(op1), op2_(op2), op1_pct_(op1_pct) {
if (op1_pct > 100)
throw std::runtime_error("invalid percentage");
}
base::req_op next_op() {
if (static_cast<unsigned>(std::rand()) % 100 > op1_pct_)
return op2_;
return op1_;
}
private:
base::req_op op1_;
base::req_op op2_;
unsigned op1_pct_;
};
//--------------------------------
class base_io_generator: public io_generator {
public:
base_io_generator(io_generator_options const &opts);
virtual bool next(base::io &next_io);
private:
sequence_generator::ptr
create_offset_generator(io_generator_options const &opts);
op_generator::ptr
create_op_generator(io_generator_options const &opts);
sequence_generator::ptr offset_gen_;
op_generator::ptr op_gen_;
sector_t block_size_;
size_t io_size_finished_;
size_t io_size_total_;
};
base_io_generator::base_io_generator(io_generator_options const &opts)
: offset_gen_(create_offset_generator(opts)),
op_gen_(create_op_generator(opts)),
block_size_(opts.block_size_),
io_size_finished_(0),
io_size_total_(opts.io_size_) {
}
bool base_io_generator::next(base::io &next_io) {
if (io_size_finished_ >= io_size_total_)
return false;
next_io.op_ = op_gen_->next_op();
next_io.sector_ = offset_gen_->next();
next_io.size_ = block_size_;
io_size_finished_ += block_size_;
return true;
}
sequence_generator::ptr
base_io_generator::create_offset_generator(io_generator_options const &opts) {
sequence_generator *gen;
if (opts.pattern_.is_random())
gen = new random_sequence_generator(opts.offset_,
opts.size_, opts.block_size_);
else
gen = new forward_sequence_generator(opts.offset_,
opts.size_, opts.block_size_);
return sequence_generator::ptr(gen);
}
op_generator::ptr
base_io_generator::create_op_generator(io_generator_options const &opts) {
// FIXME: elimiate the switch-case and hide enum values
switch (opts.pattern_.val_) {
case io_pattern::READ:
case io_pattern::RAND_READ:
return op_generator::ptr(new op_generator(base::REQ_OP_READ));
case io_pattern::WRITE:
case io_pattern::RAND_WRITE:
return op_generator::ptr(new op_generator(base::REQ_OP_WRITE));
case io_pattern::TRIM:
case io_pattern::RAND_TRIM:
return op_generator::ptr(new op_generator(base::REQ_OP_DISCARD));
case io_pattern::READ_WRITE:
case io_pattern::RAND_RW:
return op_generator::ptr(new op_generator(base::REQ_OP_READ,
base::REQ_OP_WRITE,
50));
case io_pattern::TRIM_WRITE:
case io_pattern::RAND_TW:
return op_generator::ptr(new op_generator(base::REQ_OP_DISCARD,
base::REQ_OP_WRITE,
50));
default:
throw std::runtime_error("unknown pattern");
}
}
}
//----------------------------------------------------------------
io_pattern::io_pattern()
: val_(pattern::READ) {
}
io_pattern::io_pattern(char const *pattern) {
parse(pattern);
}
void
io_pattern::parse(char const *pattern) {
bool found = false;
unsigned i = 0;
for (i = 0; i < nr_patterns; i++) {
if (!strcmp(patterns[i].first, pattern)) {
found = true;
break;
}
}
if (!found)
throw std::runtime_error("unknow pattern");
val_ = patterns[i].second;
}
bool
io_pattern::is_random() const {
return val_ & pattern::RANDOM;
}
//----------------------------------------------------------------
io_generator::ptr
base::create_io_generator(io_generator_options const &opts) {
return io_generator::ptr(new base_io_generator(opts));
}
//----------------------------------------------------------------