[benchmarking] use 2 shards for win 7 perf

Reducing the shard size when we only have 3 devices for this builder.

Bug: chromium:1152120
Change-Id: I0188d35af9a249e7356c7d02bc2820c64860cc3c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2559224
Commit-Queue: John Chen <johnchen@chromium.org>
Auto-Submit: Wenbin Zhang <wenbinzhang@google.com>
Reviewed-by: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#831025}

testing/buildbot/chromium.perf.json

@@ -173,7 +173,7 @@
           "ignore_task_failure": false,
           "io_timeout": 21600,
           "service_account": "chrome-tester@chops-service-accounts.iam.gserviceaccount.com",
-          "shards": 3
+          "shards": 2
         },
         "trigger_script": {
           "args": [

tools/perf/core/bot_platforms.py

@@ -495,7 +495,7 @@ WIN_10 = PerfPlatform(
     'Windows Intel HD 630 towers, Core i7-7700 3.6 GHz, 16GB RAM,'
     ' Intel Kaby Lake HD Graphics 630', _WIN_10_BENCHMARK_CONFIGS,
     26, 'win', executables=_WIN_10_EXECUTABLE_CONFIGS)
-WIN_7 = PerfPlatform('Win 7 Perf', 'N/A', _WIN_7_BENCHMARK_CONFIGS, 3, 'win')
+WIN_7 = PerfPlatform('Win 7 Perf', 'N/A', _WIN_7_BENCHMARK_CONFIGS, 2, 'win')
 WIN_7_GPU = PerfPlatform('Win 7 Nvidia GPU Perf', 'N/A',
                          _WIN_7_GPU_BENCHMARK_CONFIGS, 3, 'win')
 

tools/perf/core/shard_maps/timing_data/win_7_perf_timing.json

 [
     {
-        "duration": "46.0",
+        "duration": "49.0",
         "name": "loading.desktop/AirBnB_warm"
     },
     {
-        "duration": "37.0",
+        "duration": "38.0",
         "name": "loading.desktop/Aljayyash_cold"
     },
     {
-        "duration": "18.0",
+        "duration": "21.0",
         "name": "loading.desktop/AllRecipes_cold"
     },
     {
-        "duration": "25.0",
+        "duration": "24.0",
         "name": "loading.desktop/Baidu_warm"
     },
     {
-        "duration": "32.0",
+        "duration": "34.0",
         "name": "loading.desktop/Naver_cold"
     },
     {
-        "duration": "9.0",
+        "duration": "10.0",
         "name": "loading.desktop/Orange_cold"
     },
     {
-        "duration": "9.0",
+        "duration": "10.0",
         "name": "loading.desktop/Orange_warm"
     },
     {
-        "duration": "57.0",
+        "duration": "60.0",
         "name": "loading.desktop/Taobao_warm"
     },
     {
-        "duration": "48.0",
+        "duration": "51.0",
         "name": "loading.desktop/TheOnion_cold"
     },
     {
-        "duration": "26.0",
+        "duration": "27.0",
         "name": "loading.desktop/ru.wikipedia_warm"
     }
 ]
\ No newline at end of file

tools/perf/core/shard_maps/win_7_perf_map.json

@@ -2,7 +2,7 @@
     "0": {
         "benchmarks": {
             "loading.desktop": {
-                "end": 5,
+                "end": 6,
                 "abridged": true
             }
         }
@@ -10,28 +10,18 @@
     "1": {
         "benchmarks": {
             "loading.desktop": {
-                "begin": 5,
-                "end": 7,
-                "abridged": true
-            }
-        }
-    },
-    "2": {
-        "benchmarks": {
-            "loading.desktop": {
-                "begin": 7,
+                "begin": 6,
                 "abridged": true
             }
         }
     },
     "extra_infos": {
         "num_stories": 10,
-        "predicted_min_shard_time": 178.0,
+        "predicted_min_shard_time": 310.0,
         "predicted_min_shard_index": 1,
-        "predicted_max_shard_time": 224.0,
-        "predicted_max_shard_index": 2,
-        "shard #0": 212.0,
-        "shard #1": 178.0,
-        "shard #2": 224.0
+        "predicted_max_shard_time": 338.0,
+        "predicted_max_shard_index": 0,
+        "shard #0": 338.0,
+        "shard #1": 310.0
     }
 }
\ No newline at end of file