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add support for O_DIRECT/F_NOCACHE to check impact of buffer cache avoidance

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This commit is contained in:
Paul Davis 2014-12-10 13:35:57 -05:00
parent 2f300085ea
commit 500609be28
1 changed files with 36 additions and 5 deletions
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41
tools/sftest.cc
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@ -10,6 +10,7 @@
#include <stdint.h>
#include <string.h>
#include <getopt.h>
#include <fcntl.h>
#include <glibmm/miscutils.h>
@ -53,13 +54,14 @@ main (int argc, char* argv[])
{
vector<SNDFILE*> sndfiles;
uint32_t sample_size;
char optstring[] = "f:r:F:n:c:b:s";
char optstring[] = "f:r:F:n:c:b:sD";
int channels, samplerate;
char const *suffix = ".wav";
char const *header_format = "wav";
char const *data_format = "float";
uint32_t block_size = 64 * 1024;
uint32_t nfiles = 100;
bool direct = false;
const struct option longopts[] = {
{ "header-format", 1, 0, 'f' },
{ "data-format", 1, 0, 'F' },
@ -68,6 +70,7 @@ main (int argc, char* argv[])
{ "blocksize", 1, 0, 'b' },
{ "channels", 1, 0, 'c' },
{ "sync", 0, 0, 's' },
{ "direct", 0, 0, 'D' },
{ 0, 0, 0, 0 }
};
@ -105,7 +108,9 @@ main (int argc, char* argv[])
case 's':
with_sync = true;
break;
case 'D':
direct = true;
break;
default:
usage ();
return 0;
@ -167,8 +172,34 @@ main (int argc, char* argv[])
ss << suffix;
path = Glib::build_filename (tmpdirname, ss.str());
if ((sf = sf_open (path.c_str(), SFM_RDWR, &format_info)) == 0) {
int flags = O_RDWR|O_CREAT|O_TRUNC;
#ifndef __APPLE__
if (direct) {
flags |= O_DIRECT;
}
#endif
int fd = open (path.c_str(), flags, 0644);
if (fd < 0) {
cerr << "Could not open file #" << n << " @ " << path << endl;
return 1;
}
#ifdef __APPLE__
if (direct) {
/* Apple man pages say only that it returns "a value other than -1 on success",
which probably means zero, but you just can't be too careful with
those guys.
*/
if (fcntl (fd, F_NOCACHE, 1) == -1) {
cerr << "Cannot set F_NOCACHE on file # " << n << endl;
}
}
#endif
if ((sf = sf_open_fd (fd, SFM_RDWR, &format_info, true)) == 0) {
cerr << "Could not open file #" << n << " @ " << path << endl;
return 1;
}
@ -176,7 +207,7 @@ main (int argc, char* argv[])
sndfiles.push_back (sf);
}
cout << nfiles << " files are in " << tmpdirname << endl;
cout << nfiles << " files are in " << tmpdirname << " all used " << (direct ? "without" : "with") << " OS buffer cache" << endl;
cout << "Format is " << suffix << ' ' << channels << " channel" << (channels > 1 ? "s" : "") << " written in chunks of " << block_size << " frames, synced ? " << (with_sync ? "yes" : "no") << endl;
data = new float[block_size*channels];