Comments on: LINQ vs Loop – A performance test

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.

By: john

john — Fri, 22 Feb 2008 15:08:32 +0000

Pavol – the ToArray appears to take so long as the query is only executed at this point. Deferred query execution in LINQ means the query is only executed when you iterate through the query result (e.g. by calling ToArray). declaring and initialising the query doesn’t execute the query, but this initialisation probably accounts for the shorter time (2ms) you’ve seen.