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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _STORAGED_DISKSTATS_H_
#define _STORAGED_DISKSTATS_H_
#include <stdint.h>
#include <android/hardware/health/2.0/IHealth.h>
// number of attributes diskstats has
#define DISK_STATS_SIZE ( 11 )
#define MMC_DISK_STATS_PATH "/sys/block/mmcblk0/stat"
#define SDA_DISK_STATS_PATH "/sys/block/sda/stat"
struct disk_stats {
/* It will be extremely unlikely for any of the following entries to overflow.
* For read_bytes(which will be greater than any of the following entries), it
* will take 27 years to overflow uint64_t at the reading rate of 20GB/s, which
* is the peak memory transfer rate for current memory.
* The diskstats entries (first 11) need to be at top in this structure _after_
* compiler's optimization.
*/
uint64_t read_ios; // number of read I/Os processed
uint64_t read_merges; // number of read I/Os merged with in-queue I/Os
uint64_t read_sectors; // number of sectors read
uint64_t read_ticks; // total wait time for read requests
uint64_t write_ios; // number of write I/Os processed
uint64_t write_merges; // number of write I/Os merged with in-queue I/Os
uint64_t write_sectors; // number of sectors written
uint64_t write_ticks; // total wait time for write requests
uint64_t io_in_flight; // number of I/Os currently in flight
uint64_t io_ticks; // total time this block device has been active
uint64_t io_in_queue; // total wait time for all requests
uint64_t start_time; // monotonic time accounting starts
uint64_t end_time; // monotonic time accounting ends
uint32_t counter; // private counter for accumulate calculations
double io_avg; // average io_in_flight for accumulate calculations
bool is_zero() {
return read_ios == 0 && write_ios == 0 &&
io_in_flight == 0 && io_ticks == 0 && io_in_queue == 0;
}
friend disk_stats operator- (disk_stats curr, const disk_stats& prev) {
curr.read_ios -= prev.read_ios;
curr.read_merges -= prev.read_merges;
curr.read_sectors -= prev.read_sectors;
curr.read_ticks -= prev.read_ticks;
curr.write_ios -= prev.write_ios;
curr.write_merges -= prev.write_merges;
curr.write_sectors -= prev.write_sectors;
curr.write_ticks -= prev.write_ticks;
/* skips io_in_flight, use current value */
curr.io_ticks -= prev.io_ticks;
curr.io_in_queue -= prev.io_in_queue;
return curr;
}
friend bool operator== (const disk_stats& a, const disk_stats& b) {
return a.read_ios == b.read_ios &&
a.read_merges == b.read_merges &&
a.read_sectors == b.read_sectors &&
a.read_ticks == b.read_ticks &&
a.write_ios == b.write_ios &&
a.write_merges == b.write_merges &&
a.write_sectors == b.write_sectors &&
a.write_ticks == b.write_ticks &&
/* skips io_in_flight */
a.io_ticks == b.io_ticks &&
a.io_in_queue == b.io_in_queue;
}
disk_stats& operator+= (const disk_stats& stats) {
read_ios += stats.read_ios;
read_merges += stats.read_merges;
read_sectors += stats.read_sectors;
read_ticks += stats.read_ticks;
write_ios += stats.write_ios;
write_merges += stats.write_merges;
write_sectors += stats.write_sectors;
write_ticks += stats.write_ticks;
/* skips io_in_flight, use current value */
io_ticks += stats.io_ticks;
io_in_queue += stats.io_in_queue;
return *this;
}
};
struct disk_perf {
uint32_t read_perf; // read speed (kbytes/s)
uint32_t read_ios; // read I/Os per second
uint32_t write_perf; // write speed (kbytes/s)
uint32_t write_ios; // write I/Os per second
uint32_t queue; // I/Os in queue
bool is_zero() {
return read_perf == 0 && read_ios == 0 &&
write_perf == 0 && write_ios == 0 && queue == 0;
}
};
class stream_stats {
private:
double mSum;
double mSquareSum;
uint32_t mCnt;
public:
stream_stats() : mSum(0), mSquareSum(0), mCnt(0) {};
~stream_stats() {};
double get_mean() {
return mSum / mCnt;
}
double get_std() {
return sqrt(mSquareSum / mCnt - mSum * mSum / (mCnt * mCnt));
}
void add(uint32_t num) {
mSum += (double)num;
mSquareSum += (double)num * (double)num;
mCnt++;
}
void evict(uint32_t num) {
if (mSum < num || mSquareSum < (double)num * (double)num) return;
mSum -= (double)num;
mSquareSum -= (double)num * (double)num;
mCnt--;
}
};
class disk_stats_monitor {
private:
FRIEND_TEST(storaged_test, disk_stats_monitor);
const char* const DISK_STATS_PATH;
struct disk_stats mPrevious;
struct disk_stats mAccumulate; /* reset after stall */
struct disk_stats mAccumulate_pub; /* reset after publish */
bool mStall;
std::queue<struct disk_perf> mBuffer;
struct {
stream_stats read_perf; // read speed (bytes/s)
stream_stats read_ios; // read I/Os per second
stream_stats write_perf; // write speed (bytes/s)
stream_stats write_ios; // write I/O per second
stream_stats queue; // I/Os in queue
} mStats;
bool mValid;
const uint32_t mWindow;
const double mSigma;
struct disk_perf mMean;
struct disk_perf mStd;
android::sp<android::hardware::health::V2_0::IHealth> mHealth;
void update_mean();
void update_std();
void add(struct disk_perf* perf);
void evict(struct disk_perf* perf);
bool detect(struct disk_perf* perf);
void update(struct disk_stats* stats);
public:
disk_stats_monitor(const android::sp<android::hardware::health::V2_0::IHealth>& healthService,
uint32_t window_size = 5, double sigma = 1.0)
: DISK_STATS_PATH(
healthService != nullptr
? nullptr
: (access(MMC_DISK_STATS_PATH, R_OK) == 0
? MMC_DISK_STATS_PATH
: (access(SDA_DISK_STATS_PATH, R_OK) == 0 ? SDA_DISK_STATS_PATH : nullptr))),
mPrevious(),
mAccumulate(),
mAccumulate_pub(),
mStall(false),
mValid(false),
mWindow(window_size),
mSigma(sigma),
mMean(),
mStd(),
mHealth(healthService) {}
bool enabled() { return mHealth != nullptr || DISK_STATS_PATH != nullptr; }
void update(void);
void publish(void);
};
#endif /* _STORAGED_DISKSTATS_H_ */
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