Should i use ThreadPools or Task Parallel Library for IO-bound operations
So i instead decided to write tests for this and see it on practical data.
Test Legend
- Itr: Iteration
- Seq: Sequential Approach.
- PrlEx: Parallel Extensions - Parallel.ForEach
- TPL: Task Parallel Library
- TPool: ThreadPool
Test Results
Single-Core CPU [Win7-32] -- runs under VMWare --
Test Environment: 1 physical cpus, 1 cores, 1 logical cpus.
Will be parsing a total of 10 feeds.
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Itr. Seq. PrlEx TPL TPool
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#1 10.82s 04.05s 02.69s 02.60s
#2 07.48s 03.18s 03.17s 02.91s
#3 07.66s 03.21s 01.90s 01.68s
#4 07.43s 01.65s 01.70s 01.76s
#5 07.81s 02.20s 01.75s 01.71s
#6 07.67s 03.25s 01.97s 01.63s
#7 08.14s 01.77s 01.72s 02.66s
#8 08.04s 03.01s 02.03s 01.75s
#9 08.80s 01.71s 01.67s 01.75s
#10 10.19s 02.23s 01.62s 01.74s
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Avg. 08.40s 02.63s 02.02s 02.02s
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Single-Core CPU [WinXP] -- runs under VMWare --
Test Environment: 1 physical cpus, NotSupported cores, NotSupported logical cpus.
Will be parsing a total of 10 feeds.
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Itr. Seq. PrlEx TPL TPool
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#1 10.79s 04.05s 02.75s 02.13s
#2 07.53s 02.84s 02.08s 02.07s
#3 07.79s 03.74s 02.04s 02.07s
#4 08.28s 02.88s 02.73s 03.43s
#5 07.55s 02.59s 03.99s 03.19s
#6 07.50s 02.90s 02.83s 02.29s
#7 07.80s 04.32s 02.78s 02.67s
#8 07.65s 03.10s 02.07s 02.53s
#9 10.70s 02.61s 02.04s 02.10s
#10 08.98s 02.88s 02.09s 02.16s
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Avg. 08.46s 03.19s 02.54s 02.46s
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Dual-Core CPU [Win7-64]
Test Environment: 1 physical cpus, 2 cores, 2 logical cpus.
Will be parsing a total of 10 feeds.
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Itr. Seq. PrlEx TPL TPool
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#1 07.09s 02.28s 02.64s 01.79s
#2 06.04s 02.53s 01.96s 01.94s
#3 05.84s 02.18s 02.08s 02.34s
#4 06.00s 01.43s 01.69s 01.43s
#5 05.74s 01.61s 01.36s 01.49s
#6 05.92s 01.59s 01.73s 01.50s
#7 06.09s 01.44s 02.14s 02.37s
#8 06.37s 01.34s 01.46s 01.36s
#9 06.57s 01.30s 01.58s 01.67s
#10 06.06s 01.95s 02.88s 01.62s
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Avg. 06.17s 01.76s 01.95s 01.75s
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Quad-Core CPU [Win7-64] -- HyprerThreading Supported --
Test Environment: 1 physical cpus, 4 cores, 8 logical cpus.
Will be parsing a total of 10 feeds.
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Itr. Seq. PrlEx TPL TPool
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#1 10.56s 02.03s 01.71s 01.69s
#2 07.42s 01.63s 01.71s 01.69s
#3 11.66s 01.69s 01.73s 01.61s
#4 07.52s 01.77s 01.63s 01.65s
#5 07.69s 02.32s 01.67s 01.62s
#6 07.31s 01.64s 01.53s 02.17s
#7 07.44s 02.56s 02.35s 02.31s
#8 08.36s 01.93s 01.73s 01.66s
#9 07.92s 02.15s 01.72s 01.65s
#10 07.60s 02.14s 01.68s 01.68s
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Avg. 08.35s 01.99s 01.75s 01.77s
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Summarization
- Whether you run on a single-core environment or a multi-core one, Parallel Extensions, TPL and ThreadPool behaves the same and gives approximate results.
- Still TPL has advantages like easy exception handling, cancellation support and ability to easily return Task results. Though Parallel Extensions is also another viable alternative.
Running tests on your own
You can download the source here and run on-your-own. If you can post the results, i'll add them also.
Update: Fixed the source link.
If you're trying to maximize throughput for IO-bound tasks you absolutely must combine the traditional Asynchronous Processing Model (APM) APIs with your TPL based work. The APM APIs are the only way to unblock the CPU thread whilst the asynchronous IO callback is pending. The TPL provides the TaskFactory::FromAsync helper method to assist in combining APM and TPL code.
Check out this section of the .NET SDK on MSDN entitled TPL and Traditional .NET Asynchronous Programming for more information on how to combine these two programming models to achieve async nirvana.