ceph/src/test/test_rewrite_latency.cc

   1
   2 #include <unistd.h>
   3 #include <map>
   4 #include <errno.h>
   5
   6 #include "include/utime.h"
   7 #include "common/Clock.h"
   8 #include "common/errno.h"
   9
  10 using namespace std;
  11
  12 int main(int argc, const char **argv)
  13 {
  14   const char *fn = argv[1];
  15   multimap<utime_t, utime_t> latency;
  16   unsigned max = 10;
  17
  18   int fd = ::open(fn, O_CREAT|O_RDWR, 0644);
  19   if (fd < 1) {
  20     int err = errno;
  21     cerr << "failed to open " << fn << " with " << cpp_strerror(err) << std::endl;
  22     return -1;
  23   }
  24
  25   while (true) {
  26     utime_t now = ceph_clock_now();
  27     int r = ::pwrite(fd, fn, strlen(fn), 0);
  28     ceph_assert(r >= 0);
  29     utime_t lat = ceph_clock_now();
  30     lat -= now;
  31     utime_t oldmin;
  32     if (!latency.empty())
  33       oldmin = latency.begin()->first;
  34     latency.insert(make_pair(lat, now));
  35     utime_t newmin = latency.begin()->first;
  36     while (latency.size() > max)
  37       latency.erase(latency.begin());
  38     if (oldmin == newmin) {
  39       cout << "latency\tat" << std::endl;
  40       for (multimap<utime_t,utime_t>::reverse_iterator p = latency.rbegin();
  41            p != latency.rend();
  42            ++p) {
  43         cout << p->first << "\t" << p->second << std::endl;
  44       }
  45     }
  46   }
  47 }