Reduce memory allocationt. #2109

xljiulang · 2024-11-18T14:06:12Z

Now, memory allocation is reduced to 50%.
Job=.NET 8.0 Runtime=.NET 8.0

Method	PayloadSize	Mean	Error	StdDev	Ratio	RatioSD	Gen0	Gen1	Allocated	Alloc Ratio
Send_1000_Messages_New	8192	8.727 ms	0.1393 ms	0.1368 ms	1.00	0.00	1875.0000	62.5000	8.55 MB	1.00
Send_1000_Messages_Old	8192	18.182 ms	0.1461 ms	0.1220 ms	2.08	0.03	3593.7500	250.0000	16.89 MB	1.98

Send_1000_Messages_New	65536	40.791 ms	0.8041 ms	1.8475 ms	1.00	0.00	11076.9231	3307.6923	63.22 MB	1.00
Send_1000_Messages_Old	65536	32.204 ms	0.6323 ms	0.7997 ms	0.79	0.04	21200.0000	7066.6667	127.05 MB	2.01

xljiulang · 2024-11-19T08:30:08Z

After refactoring MqttBufferReader, the MQTTnet project can still be reduced to 50% of the pre-pr level, and MQTTnet.AspNetCore can be reduced to 0.58% of the pre-pr level.

Method	PayloadSize	Mean	Error	StdDev	Median	Ratio	RatioSD	Gen0	Allocated	Alloc Ratio
AspNetCore_Send_1000_Messages	1024	29.49 ms	0.568 ms	0.697 ms	29.41 ms	1.00	0.00	156.2500	738.92 KB	1.00
MQTTnet_Send_1000_Messages	1024	53.17 ms	1.041 ms	1.022 ms	53.35 ms	1.80	0.05	500.0000	2325.25 KB	3.15

AspNetCore_Send_1000_Messages	8192	32.57 ms	0.634 ms	0.802 ms	32.48 ms	1.00	0.00	125.0000	735.07 KB	1.00
MQTTnet_Send_1000_Messages	8192	54.95 ms	0.537 ms	0.476 ms	55.06 ms	1.69	0.05	2555.5556	9326.39 KB	12.69

AspNetCore_Send_1000_Messages	65536	58.99 ms	1.145 ms	1.406 ms	58.81 ms	1.00	0.00	125.0000	758.25 KB	1.00
MQTTnet_Send_1000_Messages	65536	84.97 ms	4.546 ms	13.405 ms	78.82 ms	1.31	0.10	16714.2857	66269.48 KB	87.40

…lyMemory<byte>

…lySpan<byte>

…ySpan<byte>).

…ite.

…0 allocations.

…ethods.

… the future.

…into buffer-reader

…ectly.

xljiulang · 2024-12-03T13:20:02Z

Source/MQTTnet.Extensions.Rpc/MqttRpcClientExtensions.cs

    {
-        public static Task<byte[]> ExecuteAsync(this IMqttRpcClient client, TimeSpan timeout, string methodName, string payload, MqttQualityOfServiceLevel qualityOfServiceLevel, IDictionary<string,object> parameters = null)
+        [Obsolete("Use the method ExecuteTimeOutAsync instead.")]
+        public static async Task<byte[]> ExecuteAsync(this IMqttRpcClient client, TimeSpan timeout, string methodName, string payload, MqttQualityOfServiceLevel qualityOfServiceLevel, IDictionary<string, object> parameters = null)


Do we need to keep this method to be compatible with the old version of the API prototype?
After removing these two [Obsolete] methods, we can also overload the ExecuteTimeOutAsync method to the ExecuteAsync method name, and put the TimeSpan timeout parameter in the last parameter, corresponding to the cancellationToken parameter position.

mregen · 2024-12-04T08:05:28Z

Source/MQTTnet.Benchmarks/MQTTnet.Benchmarks.csproj

        <NuGetAudit>true</NuGetAudit>
        <NuGetAuditLevel>low</NuGetAuditLevel>
-        <AnalysisLevel>latest-Recommended</AnalysisLevel>
+        <!--<AnalysisLevel>latest-Recommended</AnalysisLevel>-->


try this on .NET 9, if you commented it out because of the 100s of warning messages

<PropertyGroup> <AnalysisLevel>latest</AnalysisLevel> <AnalysisMode>recommended</AnalysisMode> <AnalysisModeStyle>default</AnalysisModeStyle> </PropertyGroup>

That's 100s of error messages! We can unify this issue in #2120.

see https://developercommunity.visualstudio.com/t/Code-Rules-that-were-Informational-are-n/10789409#TPIN-N10795393

xljiulang · 2024-12-05T12:20:13Z

Results of MessageProcessingBenchmark before and after PR.


BenchmarkDotNet v0.13.12, Windows 11 (10.0.26100.2314)
12th Gen Intel Core i5-12450H, 1 CPU, 12 logical and 8 physical cores
.NET SDK 9.0.101
  [Host]   : .NET 8.0.10 (8.0.1024.46610), X64 RyuJIT AVX2
  .NET 8.0 : .NET 8.0.10 (8.0.1024.46610), X64 RyuJIT AVX2

Job=.NET 8.0  Runtime=.NET 8.0

Method	PayloadSize	Mean	Error	StdDev	Rank	Gen0	Gen1	Allocated
Send_1000_Messages_BeforePR	1024	28.66 ms	0.563 ms	1.151 ms	1	781.2500	-	4.48 MB
Send_1000_Messages_BeforePR	4096	31.88 ms	0.237 ms	0.198 ms	2	3187.5000	187.5000	13.27 MB
Send_1000_Messages_BeforePR	8192	33.92 ms	0.208 ms	0.185 ms	3	7000.0000	866.6667	25.05 MB

Method	PayloadSize	Mean	Error	StdDev	Rank	Gen0	Allocated
Send_1000_Messages_AfterPR	1024	29.55 ms	0.229 ms	0.215 ms	1	281.2500	1.75 MB
Send_1000_Messages_AfterPR	4096	31.02 ms	0.207 ms	0.173 ms	2	281.2500	1.76 MB
Send_1000_Messages_AfterPR	8192	32.86 ms	0.172 ms	0.144 ms	3	250.0000	1.84 MB

…thod.

xljiulang · 2024-12-07T06:23:19Z

The development work of this PR has been completed, but it depends on #2115, otherwise some unit tests will fail.

…method.

chkr1011 · 2025-10-17T16:52:17Z

Samples/Client/Client_Publish_Samples.cs

-                .Build();
-
-            await mqttClient.PublishAsync(applicationMessage, CancellationToken.None);
+            await mqttClient.PublishStringAsync(


Why are the samples changed? They show how to use the message builder. Please add new samples which are targeting performance relevant ways of publising.

chkr1011 · 2025-10-17T16:53:08Z

Source/MQTTnet.Extensions.Rpc/MQTTnet.Extensions.Rpc.csproj

        <NuGetAudit>true</NuGetAudit>
        <NuGetAuditLevel>low</NuGetAuditLevel>
-        <AnalysisLevel>latest-Recommended</AnalysisLevel>
+        <!--<AnalysisLevel>latest-Recommended</AnalysisLevel>-->


Why is this commented out?

chkr1011 · 2025-10-17T16:53:35Z

Source/MQTTnet.Extensions.Rpc/IMqttRpcClient.cs

-
-        Task<byte[]> ExecuteAsync(string methodName, byte[] payload, MqttQualityOfServiceLevel qualityOfServiceLevel, IDictionary<string, object> parameters = null, CancellationToken cancellationToken = default);
+    {       
+        Task<ReadOnlySequence<byte>> ExecuteAsync(string methodName, ReadOnlySequence<byte> payload, MqttQualityOfServiceLevel qualityOfServiceLevel, IDictionary<string, object> parameters = null, CancellationToken cancellationToken = default);


This looks like a breaking change to me. Is there a way to support all three methods for now?

chkr1011 · 2025-10-17T17:03:28Z

@xljiulang I want to merge this PR but it contains too many changes and too many breaking API changes. Is there a way to split this into smaller pieces and avoiding breaking changes (for now, using obsolete attribute etc)?

xljiulang added 2 commits November 18, 2024 22:01

Reduce memory allocation of DecodePublishPacket.

a793a3a

Reduce memory allocation of MqttBufferReader.

6c7e0e5

xljiulang changed the title ~~Reduce memory allocation of DecodePublishPacket.~~ Reduce memory allocationt. Nov 19, 2024

xljiulang added 26 commits November 19, 2024 17:06

Change the type of the Packet field from ArraySegment<byte> to ReadOn…

e7f4248

…lyMemory<byte>

MqttBufferWriter.WriteBinary(byte[]) parameter type changed to ReadOn…

e578f0c

…lySpan<byte>

Change the type of PayloadSegment to ReadOnlyMemory<byte>

9fa3337

Change the type of PayloadSegment to ReadOnlyMemory<byte>

7edac8f

Optimizing MqttBufferReader

0a31a61

More byte[] parameters or properties are changed to ReadonlyMemory<byte>

8b89a54

MqttPacketInspector.FillReceiveBuffer: ReadOnlyMemory->ReadOnlySpan

b26b4eb

Add high performance payload to json deserialization extension

b1a1865

MqttBufferWriter: Rename WriteBinary(byte[],int,int) to Write(Readonl…

53242ee

…ySpan<byte>).

Using BinaryPrimitives to write length values.

42076f4

MqttBufferWriter: Use Span<byte> GetSpan(int) to get the buffer to wr…

8f76c02

…ite.

MqttConnectPacket: Restore Password to byte[]? type.

07772a1

MqttConnectPacket: Restore Password to byte[]? type.

e2ee3f8

MqttClientExtensions: Using ArrayPool makes PublishStringAsync reach …

f1593ff

…0 allocations.

Add 0 allocated MqttPayloadOwnerFactory to build mqtt Payload.

8f69184

MqttPayloadOwnerFactory: Improve implementation and add unit tests.

b992a4f

MqttServerExtensions: Add high-performance Inject related extension m…

7a61bc2

…ethods.

Add support for payloadFactory extension methods

94f0f9e

MqttPayloadOwnerFactory: CancellationToken support.

41331c5

Add PublishStreamAsync() and InjectStreamAsync()

f2367aa

Improve ConvertPayloadToJson

eb334f0

Add CreateJsonReaderOptions

180b31b

Reduce the use of unnecessary MqttApplicationMessageBuilder

58390e8

Update Client_Publish_Samples.

6664f15

SingleSegmentPayloadOwner: use payloadFactory

d1792a5

Rpc.ExecuteAsync: Reduce memory allocation.

0ed0b48

xljiulang added 4 commits December 3, 2024 20:01

Do not use the PayloadSegment field in anticipation of its removal in…

ee6b950

… the future.

Merge branch 'buffer-reader' of https://github.com/xljiulang/MQTTnet …

7ef0a2c

…into buffer-reader

ValidatingConnectionEventArgs: Restore RawPasswordto byte[]? type.

4025d18

Some PublishAsync and InjectAsync methods remove await and return dir…

8aea746

…ectly.

xljiulang commented Dec 3, 2024

View reviewed changes

xljiulang added 2 commits December 4, 2024 08:32

Merge branch 'main' into buffer-reader

c661764

ConfigureAwait(false)!

a8b6fe9

mregen reviewed Dec 4, 2024

View reviewed changes

xljiulang added 2 commits December 5, 2024 13:29

MqttChannelAdapter: Use ArrayPool to reduce memory allocation.

22aae2d

Fixed the buffer size issue of PacketInspector.

20d7866

xljiulang mentioned this pull request Dec 5, 2024

Copy the PublishPacket and then queue it #2115

Open

xljiulang added 4 commits December 5, 2024 17:14

Add more ExecuteTimeoutAsync overload methods;

c7a16a9

Update doc and unit test.

5ae8522

Enhance unit testing of MqttPayloadOwnerFactory.

d2c36ee

Update and fix MessageProcessingBenchmark.

8df3a96

MqttPacketInspector: add FillReceiveBuffer(ReadOnlySequence<byte>) me…

f2a81ea

…thod.

xljiulang mentioned this pull request Dec 6, 2024

Refactoring MQTTnet.AspNetCore #2103

Open

xljiulang added 2 commits December 7, 2024 13:34

Use Pipe to reduce the memory allocation of MqttPacketInspector.

759a816

InspectPacketAsync() is performed only in the Fill state.

52daba1

xljiulang added 5 commits December 9, 2024 22:18

Fixed the issue of writing 0-byte Binary.

83138b9

MqttBufferWriter: Add WriteFourByteInteger(uint) method.

f82344a

MqttBufferWriter: Added IBufferWriter<byte> AsLowLevelBufferWriter() …

cc09847

…method.

Fixed duplicate write of (MqttPropertyId id, ushort value).

d0e1ce4

Merge branch 'dotnet:master' into buffer-reader

057365d

chkr1011 reviewed Oct 17, 2025

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