tools/rados: allow reuse object for write test

Currently, for rados bench write test, it always
creates new objects for testing. Create operation
refers to non-neglectable metadata overhead, especially
for small write performance. This patch allows to
reuse objects for write testing

Signed-off-by: Li Wang <laurence.liwang@gmail.com>

3 files changed, 30 insertions, 19 deletions

diff --git a/src/common/obj_bencher.cc b/src/common/obj_bencher.cc
index 47b9a724492..9b0bb79fc30 100644
--- a/src/common/obj_bencher.cc
+++ b/src/common/obj_bencher.cc
@@ -239,27 +239,31 @@ int ObjBencher::aio_bench(
   uint64_t op_size, uint64_t object_size,
   unsigned max_objects,
   bool cleanup, bool hints,
-  const std::string& run_name, bool no_verify) {
+  const std::string& run_name, bool reuse_bench, bool no_verify) {
 
   if (concurrentios <= 0)
     return -EINVAL;
 
   int num_objects = 0;
   int r = 0;
-  int prevPid = 0;
+  int prev_pid = 0;
   std::chrono::duration<double> timePassed;
 
   // default metadata object is used if user does not specify one
   const std::string run_name_meta = (run_name.empty() ? BENCH_LASTRUN_METADATA : run_name);
 
   //get data from previous write run, if available
-  if (operation != OP_WRITE) {
+  if (operation != OP_WRITE || reuse_bench) {
     uint64_t prev_op_size, prev_object_size;
     r = fetch_bench_metadata(run_name_meta, &prev_op_size, &prev_object_size,
-			     &num_objects, &prevPid);
+			     &num_objects, &prev_pid);
     if (r < 0) {
-      if (r == -ENOENT)
-        cerr << "Must write data before running a read benchmark!" << std::endl;
+      if (r == -ENOENT) {
+        if (reuse_bench)
+          cerr << "Must write data before using reuse_bench for a write benchmark!" << std::endl;
+        else
+          cerr << "Must write data before running a read benchmark!" << std::endl;
+      }
       return r;
     }
     object_size = prev_object_size;   
@@ -289,21 +293,21 @@ int ObjBencher::aio_bench(
     formatter->open_object_section("bench");
 
   if (OP_WRITE == operation) {
-    r = write_bench(secondsToRun, concurrentios, run_name_meta, max_objects);
+    r = write_bench(secondsToRun, concurrentios, run_name_meta, max_objects, prev_pid);
     if (r != 0) goto out;
   }
   else if (OP_SEQ_READ == operation) {
-    r = seq_read_bench(secondsToRun, num_objects, concurrentios, prevPid, no_verify);
+    r = seq_read_bench(secondsToRun, num_objects, concurrentios, prev_pid, no_verify);
     if (r != 0) goto out;
   }
   else if (OP_RAND_READ == operation) {
-    r = rand_read_bench(secondsToRun, num_objects, concurrentios, prevPid, no_verify);
+    r = rand_read_bench(secondsToRun, num_objects, concurrentios, prev_pid, no_verify);
     if (r != 0) goto out;
   }
 
   if (OP_WRITE == operation && cleanup) {
     r = fetch_bench_metadata(run_name_meta, &op_size, &object_size,
-			     &num_objects, &prevPid);
+                            &num_objects, &prev_pid);
     if (r < 0) {
       if (r == -ENOENT)
         cerr << "Should never happen: bench metadata missing for current run!" << std::endl;
@@ -313,7 +317,7 @@ int ObjBencher::aio_bench(
     data.start_time = mono_clock::now();
     out(cout) << "Cleaning up (deleting benchmark objects)" << std::endl;
 
-    r = clean_up(num_objects, prevPid, concurrentios);
+    r = clean_up(num_objects, prev_pid, concurrentios);
     if (r != 0) goto out;
 
     timePassed = mono_clock::now() - data.start_time;
@@ -377,7 +381,7 @@ int ObjBencher::fetch_bench_metadata(const std::string& metadata_file,
 
 int ObjBencher::write_bench(int secondsToRun,
 			    int concurrentios, const string& run_name_meta,
-			    unsigned max_objects) {
+			    unsigned max_objects, int prev_pid) {
   if (concurrentios <= 0) 
     return -EINVAL;
   
@@ -397,7 +401,7 @@ int ObjBencher::write_bench(int secondsToRun,
   }
   bufferlist* newContents = 0;
 
-  std::string prefix = generate_object_prefix();
+  std::string prefix = prev_pid ? generate_object_prefix(prev_pid) : generate_object_prefix();
   if (!formatter)
     out(cout) << "Object prefix: " << prefix << std::endl;
   else
@@ -627,7 +631,7 @@ int ObjBencher::write_bench(int secondsToRun,
   encode(data.object_size, b_write);
   num_objects = (data.finished + writes_per_object - 1) / writes_per_object;
   encode(num_objects, b_write);
-  encode(getpid(), b_write);
+  encode(prev_pid ? prev_pid : getpid(),  b_write);
   encode(data.op_size, b_write);
 
   // persist meta-data for further cleanup or read
diff --git a/src/common/obj_bencher.h b/src/common/obj_bencher.h
index 0d4a5c11c91..8e41fb5bc1f 100644
--- a/src/common/obj_bencher.h
+++ b/src/common/obj_bencher.h
@@ -75,9 +75,9 @@ protected:
   struct bench_data data;
 
   int fetch_bench_metadata(const std::string& metadata_file, uint64_t* op_size,
-			   uint64_t* object_size, int* num_objects, int* prevPid);
+			   uint64_t* object_size, int* num_objects, int* prev_pid);
 
-  int write_bench(int secondsToRun, int concurrentios, const string& run_name_meta, unsigned max_objects);
+  int write_bench(int secondsToRun, int concurrentios, const string& run_name_meta, unsigned max_objects, int prev_pid);
   int seq_read_bench(int secondsToRun, int num_objects, int concurrentios, int writePid, bool no_verify=false);
   int rand_read_bench(int secondsToRun, int num_objects, int concurrentios, int writePid, bool no_verify=false);
 
@@ -112,7 +112,7 @@ public:
   int aio_bench(
     int operation, int secondsToRun,
     int concurrentios, uint64_t op_size, uint64_t object_size, unsigned max_objects,
-    bool cleanup, bool hints, const std::string& run_name, bool no_verify=false);
+    bool cleanup, bool hints, const std::string& run_name, bool reuse_bench, bool no_verify=false);
   int clean_up(const std::string& prefix, int concurrentios, const std::string& run_name);
 
   void set_show_time(bool dt) {
diff --git a/src/tools/rados/rados.cc b/src/tools/rados/rados.cc
index f879970d4b9..f3aa10834cd 100644
--- a/src/tools/rados/rados.cc
+++ b/src/tools/rados/rados.cc
@@ -103,7 +103,7 @@ void usage(ostream& out)
 "   rollback <obj-name> <snap-name>  roll back object to snap <snap-name>\n"
 "\n"
 "   listsnaps <obj-name>             list the snapshots of this object\n"
-"   bench <seconds> write|seq|rand [-t concurrent_operations] [--no-cleanup] [--run-name run_name] [--no-hints]\n"
+"   bench <seconds> write|seq|rand [-t concurrent_operations] [--no-cleanup] [--run-name run_name] [--no-hints] [--reuse-bench]\n"
 "                                    default is 16 concurrent IOs and 4 MB ops\n"
 "                                    default is to clean up after write benchmark\n"
 "                                    default run-name is 'benchmark_last_metadata'\n"
@@ -1842,6 +1842,7 @@ static int rados_tool_common(const std::map < std::string, std::string > &opts,
   int bench_write_dest = 0;
   bool cleanup = true;
   bool hints = true; // for rados bench
+  bool reuse_bench = false;
   bool no_verify = false;
   bool use_striper = false;
   bool with_clones = false;
@@ -2028,6 +2029,10 @@ static int rados_tool_common(const std::map < std::string, std::string > &opts,
   if (i != opts.end()) {
     hints = false;
   }
+  i = opts.find("reuse-bench");
+  if (i != opts.end()) {
+    reuse_bench = true;
+  }
   i = opts.find("pretty-format");
   if (i != opts.end()) {
     pretty_format = true;
@@ -3224,7 +3229,7 @@ static int rados_tool_common(const std::map < std::string, std::string > &opts,
     cout << "hints = " << (int)hints << std::endl;
     ret = bencher.aio_bench(operation, seconds,
 			    concurrent_ios, op_size, object_size,
-			    max_objects, cleanup, hints, run_name, no_verify);
+			    max_objects, cleanup, hints, run_name, reuse_bench, no_verify);
     if (ret != 0)
       cerr << "error during benchmark: " << cpp_strerror(ret) << std::endl;
     if (formatter && output)
@@ -3915,6 +3920,8 @@ int main(int argc, const char **argv)
       opts["no-cleanup"] = "true";
     } else if (ceph_argparse_flag(args, i, "--no-hints", (char*)NULL)) {
       opts["no-hints"] = "true";
+    } else if (ceph_argparse_flag(args, i, "--reuse-bench", (char*)NULL)) {
+      opts["reuse-bench"] = "true";
     } else if (ceph_argparse_flag(args, i, "--no-verify", (char*)NULL)) {
       opts["no-verify"] = "true";
     } else if (ceph_argparse_witharg(args, i, &val, "--run-name", (char*)NULL)) {