Support --bufferedio=[0,1] from db_bench. If bufferedio = 0, then the read code path clears the OS page cache after the IO is completed. The default remains as bufferedio=1

Summary:
Task ID: #

Blame Rev:

Test Plan: Revert Plan:

Differential Revision: https://reviews.facebook.net/D3429
main
Dhruba Borthakur 13 years ago
parent 33a3c6ff6c
commit 8f293b68a9
  1. 13
      db/db_bench.cc
  2. 7
      util/env_posix.cc

@ -110,6 +110,8 @@ static int FLAGS_cache_numshardbits = -1;
// Verify checksum for every block read from storage
static bool FLAGS_verify_checksum = false;
extern bool useOsBuffer;
namespace leveldb {
namespace {
@ -782,7 +784,7 @@ class Benchmark {
void ReadRandom(ThreadState* thread) {
ReadOptions options(FLAGS_verify_checksum, true);
std::string value;
int found = 0;
long found = 0;
for (long i = 0; i < reads_; i++) {
char key[100];
const int k = thread->rand.Next() % FLAGS_num;
@ -793,7 +795,7 @@ class Benchmark {
thread->stats.FinishedSingleOp();
}
char msg[100];
snprintf(msg, sizeof(msg), "(%d of %d found)", found, num_);
snprintf(msg, sizeof(msg), "(%ld of %ld found)", found, num_);
thread->stats.AddMessage(msg);
}
@ -825,7 +827,7 @@ class Benchmark {
void SeekRandom(ThreadState* thread) {
ReadOptions options(FLAGS_verify_checksum, true);
std::string value;
int found = 0;
long found = 0;
for (long i = 0; i < reads_; i++) {
Iterator* iter = db_->NewIterator(options);
char key[100];
@ -837,7 +839,7 @@ class Benchmark {
thread->stats.FinishedSingleOp();
}
char msg[100];
snprintf(msg, sizeof(msg), "(%d of %d found)", found, num_);
snprintf(msg, sizeof(msg), "(%ld of %ld found)", found, num_);
thread->stats.AddMessage(msg);
}
@ -978,6 +980,9 @@ int main(int argc, char** argv) {
} else if (sscanf(argv[i], "--verify_checksum=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
FLAGS_verify_checksum = n;
} else if (sscanf(argv[i], "--bufferedio=%d%c", &n, &junk) == 1 &&
(n == 0 || n == 1)) {
useOsBuffer = n;
} else {
fprintf(stderr, "Invalid flag '%s'\n", argv[i]);
exit(1);

@ -25,6 +25,8 @@
#include "util/logging.h"
#include "util/posix_logger.h"
bool useOsBuffer = 1; // cache data in OS buffers
namespace leveldb {
namespace {
@ -86,6 +88,9 @@ class PosixRandomAccessFile: public RandomAccessFile {
// An error: return a non-ok status
s = IOError(filename_, errno);
}
if (!useOsBuffer) {
posix_fadvise(fd_, offset, n, POSIX_FADV_DONTNEED); // free OS pages
}
return s;
}
};
@ -329,7 +334,7 @@ class PosixEnv : public Env {
int fd = open(fname.c_str(), O_RDONLY);
if (fd < 0) {
s = IOError(fname, errno);
} else if (sizeof(void*) >= 8) {
} else if (useOsBuffer && sizeof(void*) >= 8) {
// Use mmap when virtual address-space is plentiful.
uint64_t size;
s = GetFileSize(fname, &size);

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