Comments on: LINQ vs Loop – A performance test

By: funky

funky — Thu, 15 Apr 2010 14:36:25 +0000

Thanks! I was getting 50% of CPU usage by writing file to a Stream, like so:

buffer = formData.Skip(offset).Take(buffer.Length).ToArray();

After reading your comments, I’ve rewritten my code to use loop and now CPU is quiet as ever

By: Ray

Ray — Sat, 12 Sep 2009 04:03:35 +0000

My code for Linq:

for (int t = 0; t < RUNS; ++t) { int[] less = ints.Where(i => i < 10).ToArray(); }

My result: LINQ: 00:00:00.0936002, avg. 00:00:00.0000936 Loop: 00:00:00.1092002, avg. 00:00:00.0001092

By: Eric Kaufman

Eric Kaufman — Fri, 15 May 2009 19:38:48 +0000

Just wanted to add in that with .Net 4.0 they’re upgrading the compiler, and adding parallelism for LINQ queries, which I expect will change things out a lot. For those of you who did hop on the LINQ train, I would imagine that a lot of your queries might just start to work a bit quicker once the new compiler comes out.

http://www.betanews.com/article/Everyone-talk-at-once-NET-40-will-include-Parallel-Extensions/1223931673

By: Brian

Brian — Sat, 09 May 2009 18:29:11 +0000

This function does nothing, and thus benchmarking a compiled version is dangerous (so is benchmarking a debug version, but less so). A compiler will happily say, “This loop does nothing! Let’s skip it!” I’d be hesitant to trust any benchmarks that are not in use on production code…though they’re a nice tool for developers of compilers to use to check if their optimizations are working.

By: JS

JS — Wed, 25 Feb 2009 21:08:27 +0000

If you run the compiled verision of the application (.exe or .dll), LINQ actually runs faster

running out of VS is not a valid test and should not be compared.

By: Venkat

Venkat — Mon, 16 Feb 2009 04:47:19 +0000

All the times in ms.

I run the tests as Pavol suggested.

LINQ: 1, avg. 24 Loop: 92, avg. 1322

from int i / from i, There is no much difference

LINQ: 247, avg. 3803 Loop: 89, avg. 1286

By: Håvard

Håvard — Wed, 07 Jan 2009 21:56:31 +0000

Brian: Interesting, with 3.5 SP1 I get the following results:

With explicit int: Linq .446 Loop .231

And without the explicit int: Linq .431 Loop .256

This could indicate that Cast() is optimized away in SP1, but I have not verified this.

By: Brian

Brian — Tue, 09 Dec 2008 21:10:01 +0000

I ran the same test and didn't get the same results

Linq .20 Loop .08

By: Bart

Bart — Thu, 23 Oct 2008 22:56:57 +0000

An update using the latest service packs and running the same code as in your blog: the LINQ query is 5 – 6 times slower than the loop on my machine.

However, the LINQ query is probably 5 – 6 times more understandable than the loop for someone reading the code and trying to figure out what it’s doing.

By: Robert

Robert — Sun, 02 Mar 2008 22:00:09 +0000

Wow, building in release, Loop is 10x faster than Linq without doing the int cast.