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Optimize resource utilization parser for linux (#4744)
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* Optimize resource utilization parser for linux

* Change to remarks

---------

Co-authored-by: rafalmzyk <[email protected]>
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@rafal-mz
rafal-mz and rafalmzyk authored Nov 22, 2023
1 parent f34d120 commit c66f947
Showing 1 changed file with 39 additions and 47 deletions.
86 changes: 39 additions & 47 deletions ...aries/Microsoft.Extensions.Diagnostics.ResourceMonitoring/Linux/LinuxUtilizationParser.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,15 +4,16 @@
using System;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using Microsoft.Extensions.ObjectPool;
using Microsoft.Shared.Diagnostics;
using Microsoft.Shared.Pools;

namespace Microsoft.Extensions.Diagnostics.ResourceMonitoring.Linux;

/// <summary>
/// <remarks>
/// Parses Linux files to retrieve resource utilization data.
/// </summary>
/// This class is not thread safe.
/// When the same instance is called by multiple threads it may return corrupted data.
/// </remarks>
internal sealed class LinuxUtilizationParser
{
/// <remarks>
Expand Down Expand Up @@ -77,21 +78,19 @@ internal sealed class LinuxUtilizationParser

private readonly IFileSystem _fileSystem;
private readonly long _userHz;
private readonly ObjectPool<BufferWriter<char>> _buffers;
private readonly BufferWriter<char> _buffer = new();

public LinuxUtilizationParser(IFileSystem fileSystem, IUserHz userHz)
{
_fileSystem = fileSystem;
_userHz = userHz.Value;
_buffers = BufferWriterPool.CreateBufferWriterPool<char>(maxCapacity: 64);
}

public long GetCgroupCpuUsageInNanoseconds()
{
var buffer = _buffers.Get();
_fileSystem.ReadAll(_cpuacctUsage, buffer);
_fileSystem.ReadAll(_cpuacctUsage, _buffer);

var usage = buffer.WrittenSpan;
var usage = _buffer.WrittenSpan;

_ = GetNextNumber(usage, out var nanoseconds);

Expand All @@ -100,7 +99,7 @@ public long GetCgroupCpuUsageInNanoseconds()
Throw.InvalidOperationException($"Could not get cpu usage from '{_cpuacctUsage}'. Expected positive number, but got '{new string(usage)}'.");
}

_buffers.Return(buffer);
_buffer.Reset();

return nanoseconds;
}
Expand All @@ -111,15 +110,14 @@ public long GetHostCpuUsageInNanoseconds()
const int NumberOfColumnsRepresentingCpuUsage = 8;
const int NanosecondsInSecond = 1_000_000_000;

var buffer = _buffers.Get();
_fileSystem.ReadFirstLine(_procStat, buffer);
_fileSystem.ReadFirstLine(_procStat, _buffer);

var stat = buffer.WrittenSpan;
var stat = _buffer.WrittenSpan;
var total = 0L;

if (!buffer.WrittenSpan.StartsWith(StartingTokens))
if (!_buffer.WrittenSpan.StartsWith(StartingTokens))
{
Throw.InvalidOperationException($"Expected proc/stat to start with '{StartingTokens}' but it was '{new string(buffer.WrittenSpan)}'.");
Throw.InvalidOperationException($"Expected proc/stat to start with '{StartingTokens}' but it was '{new string(_buffer.WrittenSpan)}'.");
}

stat = stat.Slice(StartingTokens.Length, stat.Length - StartingTokens.Length);
Expand All @@ -142,7 +140,7 @@ public long GetHostCpuUsageInNanoseconds()
stat = stat.Slice(next, stat.Length - next);
}

_buffers.Return(buffer);
_buffer.Reset();

return (long)(total / (double)_userHz * NanosecondsInSecond);
}
Expand All @@ -166,34 +164,29 @@ public ulong GetAvailableMemoryInBytes()
{
const long UnsetCgroupMemoryLimit = 9_223_372_036_854_771_712;

var buffer = _buffers.Get();
_fileSystem.ReadAll(_memoryLimitInBytes, buffer);
_fileSystem.ReadAll(_memoryLimitInBytes, _buffer);

var memoryBuffer = buffer.WrittenSpan;
var memoryBuffer = _buffer.WrittenSpan;
_ = GetNextNumber(memoryBuffer, out var maybeMemory);

if (maybeMemory == -1)
{
Throw.InvalidOperationException($"Could not parse '{_memoryLimitInBytes}' content. Expected to find available memory in bytes but got '{new string(memoryBuffer)}' instead.");
}

_buffers.Return(buffer);
_buffer.Reset();

if (maybeMemory == UnsetCgroupMemoryLimit)
{
return GetHostAvailableMemory();
}

return (ulong)maybeMemory;
return maybeMemory == UnsetCgroupMemoryLimit
? GetHostAvailableMemory()
: (ulong)maybeMemory;
}

public ulong GetMemoryUsageInBytes()
{
const string TotalInactiveFile = "total_inactive_file";

var buffer = _buffers.Get();
_fileSystem.ReadAll(_memoryStat, buffer);
var memoryFile = buffer.WrittenSpan;
_fileSystem.ReadAll(_memoryStat, _buffer);
var memoryFile = _buffer.WrittenSpan;

var index = memoryFile.IndexOf(TotalInactiveFile.AsSpan());

Expand All @@ -210,11 +203,11 @@ public ulong GetMemoryUsageInBytes()
Throw.InvalidOperationException($"The value of total_inactive_file found in '{_memoryStat}' is not a positive number: '{new string(inactiveMemorySlice)}'.");
}

buffer.Reset();
_buffer.Reset();

_fileSystem.ReadAll(_memoryUsageInBytes, buffer);
_fileSystem.ReadAll(_memoryUsageInBytes, _buffer);

var containerMemoryUsageFile = buffer.WrittenSpan;
var containerMemoryUsageFile = _buffer.WrittenSpan;
var next = GetNextNumber(containerMemoryUsageFile, out var containerMemoryUsage);

// this file format doesn't expect to contain anything after the number.
Expand All @@ -224,7 +217,7 @@ public ulong GetMemoryUsageInBytes()
$"We tried to read '{_memoryUsageInBytes}', and we expected to get a positive number but instead it was: '{new string(containerMemoryUsageFile)}'.");
}

_buffers.Return(buffer);
_buffer.Reset();

var memoryUsage = containerMemoryUsage - inactiveMemory;

Expand All @@ -243,9 +236,8 @@ public ulong GetHostAvailableMemory()
// The value we are interested in starts with this. We just want to make sure it is true.
const string MemTotal = "MemTotal:";

var buffer = _buffers.Get();
_fileSystem.ReadFirstLine(_memInfo, buffer);
var firstLine = buffer.WrittenSpan;
_fileSystem.ReadFirstLine(_memInfo, _buffer);
var firstLine = _buffer.WrittenSpan;

if (!firstLine.StartsWith(MemTotal))
{
Expand Down Expand Up @@ -279,7 +271,7 @@ public ulong GetHostAvailableMemory()
$"We tried to convert total memory usage value from '{_memInfo}' to bytes, but we've got a unit that we don't recognize: '{new string(unit)}'.")
};

_buffers.Return(buffer);
_buffer.Reset();

return u;
}
Expand All @@ -291,9 +283,8 @@ public ulong GetHostAvailableMemory()
/// </remarks>
public float GetHostCpuCount()
{
var buffer = _buffers.Get();
_fileSystem.ReadFirstLine(_cpuSetCpus, buffer);
var stats = buffer.WrittenSpan;
_fileSystem.ReadFirstLine(_cpuSetCpus, _buffer);
var stats = _buffer.WrittenSpan;

var start = stats.IndexOf("-", StringComparison.Ordinal);

Expand All @@ -313,7 +304,7 @@ public float GetHostCpuCount()
Throw.InvalidOperationException($"Could not parse '{_cpuSetCpus}'. Expected integer based range separated by dash (like 0-8) but got '{new string(stats)}'.");
}

_buffers.Return(buffer);
_buffer.Reset();

return endCpu - startCpu + 1;
}
Expand Down Expand Up @@ -354,13 +345,13 @@ private static int GetNextNumber(ReadOnlySpan<char> buffer, out long number)

private bool TryGetCpuUnitsFromCgroups(IFileSystem fileSystem, out float cpuUnits)
{
var buffer = _buffers.Get();
fileSystem.ReadFirstLine(_cpuCfsQuotaUs, buffer);
fileSystem.ReadFirstLine(_cpuCfsQuotaUs, _buffer);

var quotaBuffer = buffer.WrittenSpan;
var quotaBuffer = _buffer.WrittenSpan;

if (quotaBuffer.IsEmpty || (quotaBuffer.Length == 2 && quotaBuffer[0] == '-' && quotaBuffer[1] == '1'))
{
_buffer.Reset();
cpuUnits = -1;
return false;
}
Expand All @@ -372,13 +363,14 @@ private bool TryGetCpuUnitsFromCgroups(IFileSystem fileSystem, out float cpuUnit
Throw.InvalidOperationException($"Could not parse '{_cpuCfsQuotaUs}'. Expected an integer but got: '{new string(quotaBuffer)}'.");
}

buffer.Reset();
_buffer.Reset();

fileSystem.ReadFirstLine(_cpuCfsPeriodUs, buffer);
var periodBuffer = buffer.WrittenSpan;
fileSystem.ReadFirstLine(_cpuCfsPeriodUs, _buffer);
var periodBuffer = _buffer.WrittenSpan;

if (periodBuffer.IsEmpty || (periodBuffer.Length == 2 && periodBuffer[0] == '-' && periodBuffer[1] == '1'))
{
_buffer.Reset();
cpuUnits = -1;
return false;
}
Expand All @@ -390,7 +382,7 @@ private bool TryGetCpuUnitsFromCgroups(IFileSystem fileSystem, out float cpuUnit
Throw.InvalidOperationException($"Could not parse '{_cpuCfsPeriodUs}'. Expected to get an integer but got: '{new string(periodBuffer)}'.");
}

_buffers.Return(buffer);
_buffer.Reset();

cpuUnits = (float)quota / period;
return true;
Expand Down

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