Better defaults for the disk cache perftest.

net/disk_cache/disk_cache_perftest.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits>
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file_enumerator.h"
@@ skipping 61 matching lines @@
   bool TimeWrite();
   bool TimeRead(WhatToRead what_to_read, const char* timer_message);
   void ResetAndEvictSystemDiskCache();
 
   // Complete perf tests.
   void CacheBackendPerformance();
 
   const size_t kFdLimitForCacheTests = 8192;
 
   const int kNumEntries = 1000;
-  const int kHeadersSize = 200;
-  const int kBodySize = 16 * 1024 - 1;
+  const int kHeadersSize = 800;
+  const int kBodySize = 256 * 1024 - 1;
 
   std::vector<TestEntry> entries_;
 
  private:
   const size_t saved_fd_limit_;
 };
 
-// Creates num_entries on the cache, and writes 200 bytes of metadata and up
-// to kBodySize of data to each entry.
+// Creates num_entries on the cache, and writes kHeaderSize bytes of metadata
+// and up to kBodySize of data to each entry.
 bool DiskCachePerfTest::TimeWrite() {
+  // TODO(gavinp): This test would be significantly more realistic if it didn't
+  // do single reads and writes. Perhaps entries should be written 64kb at a
+  // time. As well, not all entries should be created and written essentially
+  // simultaneously; some number of entries in flight at a time would be a
+  // likely better testing load.
   scoped_refptr<net::IOBuffer> buffer1(new net::IOBuffer(kHeadersSize));
   scoped_refptr<net::IOBuffer> buffer2(new net::IOBuffer(kBodySize));
 
   CacheTestFillBuffer(buffer1->data(), kHeadersSize, false);
   CacheTestFillBuffer(buffer2->data(), kBodySize, false);
 
   int expected = 0;
 
   MessageLoopHelper helper;
   CallbackTest callback(&helper, true);
@@ skipping 191 matching lines @@
     files.DeleteBlock(address[entry], false);
     EXPECT_TRUE(
         files.CreateBlock(disk_cache::RANKINGS, BlockSize(), &address[entry]));
   }
 
   timer2.Done();
   base::MessageLoop::current()->RunUntilIdle();
 }
 
 }  // namespace