YT-21657: Read block device stat through /sys/block/$device/stat.

49101c41a066a40c31c7808a34508059403b299d

3 files changed, 96 insertions, 0 deletions

diff --git a/yt/yt/core/misc/proc.cpp b/yt/yt/core/misc/proc.cpp
index e757d73ffd..2518ad1699 100644
--- a/yt/yt/core/misc/proc.cpp
+++ b/yt/yt/core/misc/proc.cpp
@@ -1529,6 +1529,43 @@ THashMap<TString, TDiskStat> GetDiskStats()
 #endif
 }
 
+TBlockDeviceStat ParseBlockDeviceStat(const TString& statLine)
+{
+    auto buffer = SplitString(statLine, " ");
+    TBlockDeviceStat result;
+    TryParseField(buffer, 0, result.ReadsCompleted);
+    TryParseField(buffer, 1, result.ReadsMerged);
+    TryParseField(buffer, 2, result.SectorsRead);
+    TryParseField(buffer, 3, result.TimeSpentReading);
+    TryParseField(buffer, 4, result.WritesCompleted);
+    TryParseField(buffer, 5, result.WritesMerged);
+    TryParseField(buffer, 6, result.SectorsWritten);
+    TryParseField(buffer, 7, result.TimeSpentWriting);
+    TryParseField(buffer, 8, result.IOCurrentlyInProgress);
+    TryParseField(buffer, 9, result.TimeSpentDoingIO);
+    TryParseField(buffer, 10, result.WeightedTimeSpentDoingIO);
+    TryParseField(buffer, 11, result.DiscardsCompleted);
+    TryParseField(buffer, 12, result.DiscardsMerged);
+    TryParseField(buffer, 13, result.SectorsDiscarded);
+    TryParseField(buffer, 14, result.TimeSpentDiscarding);
+    TryParseField(buffer, 15, result.FlushesCompleted);
+    TryParseField(buffer, 16, result.TimeSpentFlushing);
+    return result;
+}
+
+std::optional<TBlockDeviceStat> GetBlockDeviceStat(const TString& deviceName)
+{
+#ifdef _linux_
+    const TString path = Format("/sys/block/%v/stat", deviceName);
+    TFileInput diskStatsFile(path);
+    auto data = diskStatsFile.ReadAll();
+    return ParseBlockDeviceStat(Strip(data));
+#else
+    Y_UNUSED(deviceName);
+    return std::nullopt;
+#endif
+}
+
 std::vector<TString> ListDisks()
 {
 #ifdef _linux_
diff --git a/yt/yt/core/misc/proc.h b/yt/yt/core/misc/proc.h
index 1248d66a5c..7eafd72113 100644
--- a/yt/yt/core/misc/proc.h
+++ b/yt/yt/core/misc/proc.h
@@ -343,8 +343,37 @@ struct TDiskStat
 
 TDiskStat ParseDiskStat(const TString& statLine);
 
+// See https://docs.kernel.org/block/stat.html for more info.
+struct TBlockDeviceStat
+{
+    i64 ReadsCompleted = 0;
+    i64 ReadsMerged = 0;
+    i64 SectorsRead = 0;
+    TDuration TimeSpentReading;
+
+    i64 WritesCompleted = 0;
+    i64 WritesMerged = 0;
+    i64 SectorsWritten = 0;
+    TDuration TimeSpentWriting;
+
+    i64 IOCurrentlyInProgress = 0;
+    TDuration TimeSpentDoingIO;
+    TDuration WeightedTimeSpentDoingIO;
+
+    i64 DiscardsCompleted = 0;
+    i64 DiscardsMerged = 0;
+    i64 SectorsDiscarded = 0;
+    TDuration TimeSpentDiscarding;
+
+    i64 FlushesCompleted = 0;
+    TDuration TimeSpentFlushing;
+};
+
+TBlockDeviceStat ParseBlockDeviceStat(const TString& statLine);
+
 //! DeviceName to stat info
 THashMap<TString, TDiskStat> GetDiskStats();
+std::optional<TBlockDeviceStat> GetBlockDeviceStat(const TString& deviceName);
 std::vector<TString> ListDisks();
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/yt/yt/core/misc/unittests/proc_ut.cpp b/yt/yt/core/misc/unittests/proc_ut.cpp
index f18e462aef..ed8bca5cb5 100644
--- a/yt/yt/core/misc/unittests/proc_ut.cpp
+++ b/yt/yt/core/misc/unittests/proc_ut.cpp
@@ -165,6 +165,36 @@ TEST(TProcTest, DiskStat)
     }
 }
 
+TEST(TProcTest, BlockDeviceStat)
+{
+    {
+        auto stat = ParseBlockDeviceStat("509883438 87421933 206345875260 1643399993 1892382802 4495364138 837307482336 2391271400 0 2964131914 3304110410 0 0 0 0 81921472 3564406312");
+        EXPECT_EQ(stat.ReadsCompleted, 509883438ll);
+        EXPECT_EQ(stat.ReadsMerged, 87421933ll);
+        EXPECT_EQ(stat.SectorsRead, 206345875260ll);
+        EXPECT_EQ(stat.TimeSpentReading, TDuration::MilliSeconds(1643399993ul));
+        EXPECT_EQ(stat.WritesCompleted, 1892382802ll);
+        EXPECT_EQ(stat.WritesMerged, 4495364138ll);
+        EXPECT_EQ(stat.SectorsWritten, 837307482336ll);
+        EXPECT_EQ(stat.TimeSpentWriting, TDuration::MilliSeconds(2391271400ul));
+        EXPECT_EQ(stat.IOCurrentlyInProgress, 0ll);
+        EXPECT_EQ(stat.TimeSpentDoingIO, TDuration::MilliSeconds(2964131914ul));
+        EXPECT_EQ(stat.WeightedTimeSpentDoingIO, TDuration::MilliSeconds(3304110410ul));
+        EXPECT_EQ(stat.DiscardsCompleted, 0ll);
+        EXPECT_EQ(stat.DiscardsMerged, 0ll);
+        EXPECT_EQ(stat.SectorsDiscarded, 0ll);
+        EXPECT_EQ(stat.TimeSpentDiscarding, TDuration::MilliSeconds(0ul));
+        EXPECT_EQ(stat.FlushesCompleted, 81921472ll);
+        EXPECT_EQ(stat.TimeSpentFlushing, TDuration::MilliSeconds(3564406312ul));
+    }
+    {
+        for (const TString& disk : ListDisks()) {
+            auto stat = GetBlockDeviceStat(disk);
+            EXPECT_TRUE(stat);
+        }
+    }
+}
+
 TEST(TProcTest, FileDescriptorCount)
 {
     auto initialCount = GetFileDescriptorCount();