04-Performance.md

title	section
Performance	AngleSharp.Core

Performance Evaluations

General Considerations

The library is not small (it's not huge either), which makes preloading or "warming-up" (or using NGen) a candidate for productive usage. The first runs will always be slower than the following. This is a property of C# / the MSIL (or the JIT process in general), which has nothing to do with AngleSharp.

AngleSharp has been written with performance in mind. Actually the priority is:

1. Standard conformance
2. Performance
3. Helpers / extensions
4. Tooling

Even though there are still optimizations possible (since everything had to be working first, i.e. standard conformance has been considered), the performance is promising. Parsers in established web browsers (usually written in C/C++) will still have a faster execution time, but for a completely managed process the whole parsing / DOM creation procedure is very fast.

In the following AngleSharp will be compared to other popular libraries, which are either very popular (like the HtmlAgilityPack) or ambitious (like CsQuery).

Comparison with the Html Agility Pack

The Html Agility Pack (HAP) is a good comparison target, since it is most used and established since a long time. Obviously AngleSharp is a great replacement for HAP due to the following reasons:

• Standardized HTML5 parsing model
• Much better error correction / handling
• Also parses SVG / MathML elements correctly
• Can handle CSS (selectors, rules, ...)
• Better performance

While the first points are all quite obvious and clear (that is why AngleSharp has been developed in the first place), the last point is controversial.

To proof this point a small test program has been written. The following code snippet represents the kernel of this program.

static async Task<Int64> Test(Func<String, Int64> test, String source)
{
    var min = Int64.MaxValue;

    for (int i = 0; i < 20; i++) {
        min = Math.Min(min, await Task.Run(() => test(source)));
    }

    return min;
}

static Int64 TestAngle(String source)
{
    var sw = Stopwatch.StartNew();
    var parser = new HtmlParser(source);
    parser.Parse();
    sw.Stop();
    return sw.ElapsedMilliseconds;
}

static Int64 TestAgility(String source)
{
    var sw = Stopwatch.StartNew();
    var document = new HtmlDocument();
    document.LoadHtml(source);
    sw.Stop();
    return sw.ElapsedMilliseconds;
}

This program then calls the Test method with the source code of several webpages. All of them are quite important / used very often and some of them are quite big. The biggest is definitely the official W3C syntax specification.

The following image shows the outcome of running this test. (caution: Outdated versions of all included parser; just for illustration)

Note that we took the lowest wall-time in 20 trials. The outcome details change slightly if we take the average - since AngleSharp has more code-paths and therefore requires a greater mix in warm-up runs than the HAP, however, the overall outcome is still the same with AngleSharp being faster.

The only entry where HAP excels is "GoogleNews". This is, however, a false impression. The true speedup comes from omitting the (large) inline style-sheet. Here AngleSharp has to parse CSS as well, which of course takes some additional time. The official benchmark program below excludes such edge cases by disabling CSS parsing (therefore only HTML parsing is benchmarked as intended).

Comparison with CsQuery / validator.nu HTML Parser

The CsQuery project aims to be a C# port of jQuery. To parse HTML a port of the validator.nu HTML5 engine has been selected. The validity of the resulting DOM should therefore on roughly the same level as AngleSharp, however, missing important elements such as template or main. The above image also includes the performance measurement for the HTML parser.

The parsing performance is mixed compared to AngleSharp. AngleSharp has been measured in an early stage (v0.8.6), i.e. it is likely that the performance of AngleSharp will increase even further. While the CsQuery project is ambitious and contains some interesting ideas and features, AngleSharp tries to solve the problem from the other side - follow the standards first and add nice features on top afterwards. The past has shown that implementing fancy features or a non-standard, but better, API first, will lead to problems later on.

In general there are areas where AngleSharp is performing better, and other pages where the validator.nu parser is faster. In most cases the winner does not really matter (cases such as 2ms vs 3ms).

Comparison with Other Solutions

One could also make comparisons to other projects. In the official Performance project (contained in the Visual Studio solution) you will find the Majestic (Majestic 13) parser. This one is nearly always faster than any other solution. Is it the right choice for your project? Probably not. The reason is simple: Majestic does not build a DOM, it also does not care about special tags, meanings and the HTML error correction. Basically Majestic is AngleSharp reduced to its tokenizer, with the tokenizer being a bit simpler.

This is also the reason for excluding Majestic from the performance comparison. However, you are (for your own pleasure) of course allowed to include Majestic again. The code is already checked-in.

Current Performance

Performance is valued high - even though standard-compliance is valued higher. AngleSharp's repository comes with a set of benchmarks.

HTML Parser

The setup for this test was:

BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19042
AMD Ryzen 7 2700X, 1 CPU, 16 logical and 8 physical cores
  [Host]   : .NET Framework 4.8 (4.8.4341.0), X64 RyuJIT
  ShortRun : .NET Framework 4.8 (4.8.4341.0), X64 RyuJIT

Job=ShortRun  IterationCount=3  LaunchCount=1
WarmupCount=3

The results are displayed below.

Method	UrlTest	Mean	Error	StdDev	Gen 0	Gen 1	Gen 2	Allocated
CsQuery	163	26,572.23 μs	8,325.645 μs	456.357 μs	3500.0000	843.7500	312.5000	17524.19 KB
HTMLAgilityPack	163	31,582.19 μs	10,016.229 μs	549.023 μs	2687.5000	937.5000	312.5000	15171.18 KB
AngleSharp	163	33,778.85 μs	2,390.223 μs	131.016 μs	1866.6667	800.0000	266.6667	11667.82 KB
CsQuery	360.cn	5,183.12 μs	388.822 μs	21.313 μs	421.8750	210.9375	-	2170.52 KB
HTMLAgilityPack	360.cn	5,995.97 μs	217.311 μs	11.912 μs	585.9375	289.0625	-	3530.83 KB
AngleSharp	360.cn	9,059.31 μs	1,809.919 μs	99.208 μs	468.7500	234.3750	31.2500	2350.3 KB
CsQuery	aliexpress	1,048.39 μs	76.373 μs	4.186 μs	167.9688	54.6875	-	610.8 KB
HTMLAgilityPack	aliexpress	2,426.29 μs	501.179 μs	27.471 μs	640.6250	179.6875	15.6250	2251.48 KB
AngleSharp	aliexpress	2,058.30 μs	334.734 μs	18.348 μs	156.2500	58.5938	-	591.33 KB
CsQuery	amazon	109.46 μs	7.386 μs	0.405 μs	138.6719	-	-	106.57 KB
HTMLAgilityPack	amazon	57.12 μs	0.217 μs	0.012 μs	32.9590	-	-	25.33 KB
AngleSharp	amazon	108.14 μs	5.729 μs	0.314 μs	32.5928	-	-	25.07 KB
CsQuery	ask	2,855.16 μs	136.272 μs	7.470 μs	386.7188	175.7813	42.9688	1917.87 KB
HTMLAgilityPack	ask	6,720.90 μs	654.156 μs	35.856 μs	1187.5000	585.9375	-	6688.45 KB
AngleSharp	ask	5,309.43 μs	440.766 μs	24.160 μs	296.8750	156.2500	70.3125	1789.05 KB
CsQuery	baidu	9,185.98 μs	2,700.571 μs	148.027 μs	12015.6250	11531.2500	11109.3750	58430.78 KB
HTMLAgilityPack	baidu	19,836.76 μs	1,686.464 μs	92.441 μs	28000.0000	968.7500	-	25856.31 KB
AngleSharp	baidu	5,330.41 μs	1,213.111 μs	66.495 μs	679.6875	593.7500	414.0625	2754.81 KB
CsQuery	bing	1,787.21 μs	173.355 μs	9.502 μs	851.5625	421.8750	-	4629.7 KB
HTMLAgilityPack	bing	4,301.44 μs	237.596 μs	13.023 μs	1671.8750	335.9375	62.5000	4831.79 KB
AngleSharp	bing	2,191.32 μs	107.560 μs	5.896 μs	183.5938	89.8438	-	798.45 KB
CsQuery	blogspot	118.00 μs	4.659 μs	0.255 μs	89.2334	-	-	68.8 KB
HTMLAgilityPack	blogspot	224.73 μs	18.088 μs	0.991 μs	291.2598	-	-	224.22 KB
AngleSharp	blogspot	284.27 μs	21.215 μs	1.163 μs	106.4453	8.7891	-	91.93 KB
CsQuery	codeproject	7,574.01 μs	1,090.559 μs	59.777 μs	19085.9375	750.0000	351.5625	29326.3 KB
HTMLAgilityPack	codeproject	8,439.77 μs	1,165.335 μs	63.876 μs	2234.3750	656.2500	15.6250	8052.49 KB
AngleSharp	codeproject	4,944.07 μs	142.958 μs	7.836 μs	312.5000	164.0625	39.0625	1648.52 KB
CsQuery	ebay	8,113.73 μs	813.583 μs	44.595 μs	828.1250	484.3750	156.2500	4488.56 KB
HTMLAgilityPack	ebay	13,586.42 μs	817.790 μs	44.826 μs	1921.8750	578.1250	218.7500	9665.77 KB
AngleSharp	ebay	13,333.32 μs	3,862.157 μs	211.698 μs	703.1250	468.7500	203.1250	3515.6 KB
CsQuery	en.wikipedia	28,638.36 μs	3,969.680 μs	217.592 μs	1687.5000	781.2500	218.7500	9941.59 KB
HTMLAgilityPack	en.wikipedia	50,891.40 μs	28,096.639 μs	1,540.072 μs	2800.0000	1200.0000	400.0000	14571.52 KB
AngleSharp	en.wikipedia	40,260.49 μs	9,929.362 μs	544.262 μs	1692.3077	923.0769	307.6923	9609.23 KB
CsQuery	flickr	5,523.62 μs	528.198 μs	28.952 μs	2187.5000	1953.1250	1343.7500	11630.04 KB
HTMLAgilityPack	flickr	16,674.56 μs	1,738.980 μs	95.319 μs	11187.5000	343.7500	125.0000	18192.6 KB
AngleSharp	flickr	8,770.69 μs	3,034.916 μs	166.354 μs	640.6250	531.2500	359.3750	2906.85 KB
CsQuery	florian-rappl	707.50 μs	25.038 μs	1.372 μs	142.5781	39.0625	-	326.33 KB
HTMLAgilityPack	florian-rappl	713.63 μs	90.272 μs	4.948 μs	134.7656	40.0391	-	457.35 KB
AngleSharp	florian-rappl	1,227.61 μs	69.995 μs	3.837 μs	121.0938	39.0625	-	342.15 KB
CsQuery	godaddy	6,863.21 μs	385.012 μs	21.104 μs	843.7500	421.8750	70.3125	3965.29 KB
HTMLAgilityPack	godaddy	17,099.53 μs	2,352.418 μs	128.944 μs	3156.2500	562.5000	218.7500	14457.44 KB
AngleSharp	godaddy	10,710.47 μs	4,228.312 μs	231.768 μs	531.2500	312.5000	125.0000	2959.15 KB
CsQuery	google	2,475.83 μs	66.243 μs	3.631 μs	1820.3125	511.7188	35.1563	6307.94 KB
HTMLAgilityPack	google	8,117.38 μs	889.700 μs	48.767 μs	8265.6250	531.2500	46.8750	9687.47 KB
AngleSharp	google	2,852.58 μs	207.706 μs	11.385 μs	230.4688	121.0938	54.6875	1118.61 KB
CsQuery	html5rocks	165.07 μs	5.314 μs	0.291 μs	96.4355	9.2773	-	91.02 KB
HTMLAgilityPack	html5rocks	185.48 μs	21.314 μs	1.168 μs	129.6387	16.1133	-	143.17 KB
AngleSharp	html5rocks	344.76 μs	10.928 μs	0.599 μs	102.0508	8.7891	-	94.98 KB
CsQuery	html5test	549.88 μs	29.206 μs	1.601 μs	347.6563	96.6797	-	812.11 KB
HTMLAgilityPack	html5test	1,100.92 μs	113.205 μs	6.205 μs	412.1094	136.7188	-	1225.64 KB
AngleSharp	html5test	832.16 μs	80.749 μs	4.426 μs	127.9297	41.9922	-	326.65 KB
CsQuery	huffingtonpost	19,952.34 μs	12,220.195 μs	669.830 μs	5125.0000	2156.2500	1218.7500	20271.86 KB
HTMLAgilityPack	huffingtonpost	23,360.13 μs	267.385 μs	14.656 μs	13531.2500	687.5000	187.5000	19993.95 KB
AngleSharp	huffingtonpost	21,286.14 μs	1,466.969 μs	80.410 μs	1093.7500	718.7500	343.7500	5560.22 KB
CsQuery	imdb	28,846.69 μs	13,103.589 μs	718.252 μs	6937.5000	2093.7500	1406.2500	53164.72 KB
HTMLAgilityPack	imdb	53,782.78 μs	14,400.153 μs	789.321 μs	46000.0000	1700.0000	600.0000	47500.36 KB
AngleSharp	imdb	33,662.42 μs	4,272.336 μs	234.181 μs	1666.6667	1200.0000	533.3333	10612.3 KB
CsQuery	kickass.to	62.52 μs	15.028 μs	0.824 μs	34.4238	-	-	26.47 KB
HTMLAgilityPack	kickass.to	21.91 μs	4.389 μs	0.241 μs	26.5198	-	-	20.39 KB
AngleSharp	kickass.to	48.39 μs	10.936 μs	0.599 μs	21.8506	-	-	16.79 KB
CsQuery	linkedin	3,926.10 μs	765.055 μs	41.935 μs	289.0625	140.6250	23.4375	1599.7 KB
HTMLAgilityPack	linkedin	3,327.32 μs	415.856 μs	22.794 μs	343.7500	171.8750	-	1832.89 KB
AngleSharp	linkedin	5,978.55 μs	261.960 μs	14.359 μs	257.8125	125.0000	54.6875	1385.39 KB
CsQuery	live	1,896.05 μs	90.959 μs	4.986 μs	162.1094	70.3125	-	875.95 KB
HTMLAgilityPack	live	1,728.75 μs	160.758 μs	8.812 μs	189.4531	93.7500	-	1068.87 KB
AngleSharp	live	2,967.42 μs	374.529 μs	20.529 μs	148.4375	74.2188	-	783.66 KB
CsQuery	mail.ru	14,738.88 μs	12,151.966 μs	666.090 μs	55000.0000	1640.6250	593.7500	62888.42 KB
HTMLAgilityPack	mail.ru	20,945.32 μs	6,117.784 μs	335.336 μs	14500.0000	406.2500	187.5000	22585.69 KB
AngleSharp	mail.ru	10,070.01 μs	757.617 μs	41.528 μs	656.2500	468.7500	250.0000	3241.27 KB
CsQuery	msn	10,318.80 μs	2,216.914 μs	121.517 μs	1406.2500	625.0000	78.1250	6484.48 KB
HTMLAgilityPack	msn	11,391.01 μs	998.940 μs	54.755 μs	2875.0000	859.3750	15.6250	7951.19 KB
AngleSharp	msn	16,140.33 μs	613.836 μs	33.646 μs	781.2500	468.7500	125.0000	4571.39 KB
CsQuery	myspace	22,910.76 μs	2,477.144 μs	135.781 μs	62437.5000	781.2500	250.0000	62789.61 KB
HTMLAgilityPack	myspace	20,529.88 μs	5,132.015 μs	281.303 μs	1781.2500	781.2500	250.0000	10333.3 KB
AngleSharp	myspace	20,662.87 μs	1,721.811 μs	94.378 μs	906.2500	437.5000	125.0000	5388.78 KB
CsQuery	nbc	153,610.90 μs	241,305.708 μs	13,226.780 μs	42000.0000	39000.0000	38000.0000	847835.7 KB
HTMLAgilityPack	nbc	131,026.33 μs	252,456.797 μs	13,838.009 μs	163750.0000	1500.0000	500.0000	142509.96 KB
AngleSharp	nbc	68,009.41 μs	10,392.195 μs	569.631 μs	3125.0000	1250.0000	500.0000	30147.35 KB
CsQuery	neobux	157.14 μs	5.539 μs	0.304 μs	99.3652	5.6152	-	86.08 KB
HTMLAgilityPack	neobux	216.95 μs	6.915 μs	0.379 μs	216.3086	14.8926	-	199.43 KB
AngleSharp	neobux	266.50 μs	9.616 μs	0.527 μs	85.9375	2.9297	-	69.35 KB
CsQuery	netflix	7,751.63 μs	6,590.316 μs	361.237 μs	7031.2500	5687.5000	5093.7500	36962.4 KB
HTMLAgilityPack	netflix	20,402.40 μs	532.399 μs	29.183 μs	30218.7500	187.5000	62.5000	28514.5 KB
AngleSharp	netflix	5,932.85 μs	370.366 μs	20.301 μs	781.2500	718.7500	500.0000	3935.91 KB
CsQuery	news.google	15,521.61 μs	1,692.227 μs	92.757 μs	15578.1250	12843.7500	11515.6250	66116.9 KB
HTMLAgilityPack	news.google	22,252.10 μs	1,478.085 μs	81.019 μs	27093.7500	968.7500	-	26119.47 KB
AngleSharp	news.google	11,707.40 μs	923.723 μs	50.632 μs	1015.6250	1000.0000	656.2500	4325.95 KB
CsQuery	nytimes	124,187.17 μs	251,118.584 μs	13,764.657 μs	49000.0000	46000.0000	45000.0000	718302.89 KB
HTMLAgilityPack	nytimes	95,744.94 μs	7,128.314 μs	390.727 μs	156333.3333	333.3333	166.6667	135003.91 KB
AngleSharp	nytimes	27,782.88 μs	10,274.712 μs	563.192 μs	1187.5000	781.2500	375.0000	17691.08 KB
CsQuery	pcmag	62.39 μs	1.935 μs	0.106 μs	36.1328	-	-	27.81 KB
HTMLAgilityPack	pcmag	45.43 μs	3.050 μs	0.167 μs	65.0024	-	-	49.94 KB
AngleSharp	pcmag	52.58 μs	4.139 μs	0.227 μs	23.8647	-	-	18.36 KB
CsQuery	peace(...)emark [22]	990.19 μs	81.206 μs	4.451 μs	144.5313	46.8750	-	460.6 KB
HTMLAgilityPack	peace(...)emark [22]	1,367.17 μs	120.318 μs	6.595 μs	218.7500	103.5156	-	1039.6 KB
AngleSharp	peace(...)emark [22]	1,632.73 μs	134.103 μs	7.351 μs	119.1406	46.8750	-	499.36 KB
CsQuery	pinterest	1,081.07 μs	115.151 μs	6.312 μs	537.1094	226.5625	146.4844	2078.93 KB
HTMLAgilityPack	pinterest	5,919.82 μs	683.017 μs	37.438 μs	7679.6875	210.9375	62.5000	7936.13 KB
AngleSharp	pinterest	2,269.28 μs	142.931 μs	7.835 μs	136.7188	128.9063	128.9063	1121.95 KB
CsQuery	qq	6,051.05 μs	521.770 μs	28.600 μs	453.1250	226.5625	31.2500	2471.28 KB
HTMLAgilityPack	qq	5,935.02 μs	478.857 μs	26.248 μs	593.7500	296.8750	-	3345.35 KB
AngleSharp	qq	8,620.11 μs	605.321 μs	33.180 μs	406.2500	203.1250	46.8750	2134.35 KB
CsQuery	reddit	28,485.33 μs	16,629.956 μs	911.544 μs	7343.7500	6656.2500	5937.5000	97804.74 KB
HTMLAgilityPack	reddit	55,492.40 μs	2,706.110 μs	148.331 μs	74000.0000	400.0000	200.0000	68976.93 KB
AngleSharp	reddit	18,756.14 μs	3,652.892 μs	200.227 μs	1343.7500	1125.0000	687.5000	8795.31 KB
CsQuery	sitepoint	5,456.44 μs	75.188 μs	4.121 μs	1039.0625	648.4375	328.1250	3999.25 KB
HTMLAgilityPack	sitepoint	9,606.40 μs	996.101 μs	54.600 μs	2796.8750	484.3750	46.8750	7479.26 KB
AngleSharp	sitepoint	11,834.08 μs	1,248.806 μs	68.451 μs	718.7500	437.5000	187.5000	3421.89 KB
CsQuery	smashing	107.09 μs	3.101 μs	0.170 μs	76.1719	-	-	58.63 KB
HTMLAgilityPack	smashing	97.93 μs	8.065 μs	0.442 μs	118.7744	-	-	91.27 KB
AngleSharp	smashing	146.05 μs	9.340 μs	0.512 μs	55.4199	-	-	42.68 KB
CsQuery	sohu	8,609.93 μs	1,500.603 μs	82.253 μs	546.8750	281.2500	62.5000	3279.43 KB
HTMLAgilityPack	sohu	8,968.81 μs	633.634 μs	34.732 μs	765.6250	375.0000	-	4585.71 KB
AngleSharp	sohu	13,511.16 μs	3,160.689 μs	173.248 μs	546.8750	328.1250	109.3750	3361.91 KB
CsQuery	spiegel	211,519.63 μs	372,492.375 μs	20,417.564 μs	34000.0000	15000.0000	10000.0000	576924.01 KB
HTMLAgilityPack	spiegel	75,016.80 μs	53,364.569 μs	2,925.092 μs	12125.0000	2125.0000	750.0000	31002.63 KB
AngleSharp	spiegel	76,223.27 μs	10,207.845 μs	559.526 μs	3000.0000	1000.0000	-	17287.29 KB
CsQuery	stackoverflow	7,908.16 μs	24.694 μs	1.354 μs	687.5000	343.7500	46.8750	4275.74 KB
HTMLAgilityPack	stackoverflow	6,521.56 μs	373.698 μs	20.484 μs	718.7500	343.7500	-	3761.42 KB
AngleSharp	stackoverflow	11,342.72 μs	171.985 μs	9.427 μs	515.6250	296.8750	93.7500	2645.64 KB
CsQuery	taobao	8,823.25 μs	4,057.001 μs	222.378 μs	10671.8750	3562.5000	2468.7500	28015.66 KB
HTMLAgilityPack	taobao	24,314.95 μs	2,437.444 μs	133.605 μs	29437.5000	906.2500	31.2500	30738.97 KB
AngleSharp	taobao	7,903.38 μs	422.405 μs	23.153 μs	953.1250	828.1250	546.8750	4200.56 KB
CsQuery	tmall	20,233.00 μs	9,593.654 μs	525.861 μs	35156.2500	24750.0000	22781.2500	132866.65 KB
HTMLAgilityPack	tmall	3,106.31 μs	365.161 μs	20.016 μs	761.7188	238.2813	-	2274 KB
AngleSharp	tmall	3,624.70 μs	51.738 μs	2.836 μs	234.3750	175.7813	175.7813	1540.94 KB
CsQuery	tumblr	1,257.62 μs	103.290 μs	5.662 μs	187.5000	62.5000	-	591.96 KB
HTMLAgilityPack	tumblr	1,522.42 μs	12.835 μs	0.704 μs	210.9375	101.5625	-	1236.02 KB
AngleSharp	tumblr	2,845.86 μs	119.163 μs	6.532 μs	148.4375	58.5938	-	659.3 KB
CsQuery	vk	2,879.40 μs	307.347 μs	16.847 μs	1398.4375	472.6563	468.7500	6900.75 KB
HTMLAgilityPack	vk	5,018.50 μs	932.314 μs	51.103 μs	1039.0625	492.1875	-	6016.33 KB
AngleSharp	vk	2,900.81 μs	79.652 μs	4.366 μs	214.8438	156.2500	156.2500	1174.17 KB
CsQuery	weibo	6,864.06 μs	753.160 μs	41.283 μs	64468.7500	1523.4375	328.1250	55621.54 KB
HTMLAgilityPack	weibo	6,301.79 μs	533.409 μs	29.238 μs	6210.9375	242.1875	78.1250	7947.5 KB
AngleSharp	weibo	1,957.82 μs	58.780 μs	3.222 μs	203.1250	85.9375	35.1563	972.91 KB
CsQuery	wordpress	1,548.06 μs	51.681 μs	2.833 μs	197.2656	76.1719	-	715.13 KB
CsQuery	wordpress	1,517.53 μs	86.715 μs	4.753 μs	197.2656	76.1719	-	715.13 KB
HTMLAgilityPack	wordpress	2,479.26 μs	82.376 μs	4.515 μs	546.8750	203.1250	-	1891.62 KB
HTMLAgilityPack	wordpress	2,492.86 μs	109.191 μs	5.985 μs	546.8750	203.1250	-	1891.62 KB
AngleSharp	wordpress	3,326.00 μs	172.623 μs	9.462 μs	171.8750	82.0313	-	898.76 KB
AngleSharp	wordpress	3,315.28 μs	70.997 μs	3.892 μs	171.8750	82.0313	-	898.76 KB
CsQuery	yahoo	23,053.18 μs	13,648.954 μs	748.145 μs	12718.7500	11000.0000	9250.0000	74161.32 KB
HTMLAgilityPack	yahoo	42,640.78 μs	5,029.334 μs	275.675 μs	45500.0000	333.3333	166.6667	49719.34 KB
AngleSharp	yahoo	19,797.23 μs	910.398 μs	49.902 μs	1468.7500	1187.5000	718.7500	7284.6 KB
CsQuery	youtube	183.10 μs	4.834 μs	0.265 μs	103.7598	14.4043	-	108.58 KB
HTMLAgilityPack	youtube	368.96 μs	45.489 μs	2.493 μs	324.7070	39.5508	-	346.6 KB
AngleSharp	youtube	454.85 μs	41.482 μs	2.274 μs	119.6289	20.0195	-	144.41 KB

DOM Querying / CSS Selectors

The setup for this test was:

BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19042
AMD Ryzen 7 2700X, 1 CPU, 16 logical and 8 physical cores
  [Host]   : .NET Framework 4.8 (4.8.4341.0), X64 RyuJIT
  ShortRun : .NET Framework 4.8 (4.8.4341.0), X64 RyuJIT

Job=ShortRun  IterationCount=3  LaunchCount=1
WarmupCount=3

The results are displayed below.

Method	Selector	Mean	Error	StdDev	Gen 0	Gen 1	Gen 2	Allocated
CsQuery	#title	2.866 μs	0.1455 μs	0.0080 μs	4.4479	-	-	3.42 KB
AngleSharp	#title	313.784 μs	13.9545 μs	0.7649 μs	21.4844	-	-	16.91 KB
CsQuery	.note	7.283 μs	1.2611 μs	0.0691 μs	8.1787	-	-	6.28 KB
AngleSharp	.note	326.217 μs	25.8384 μs	1.4163 μs	21.9727	-	-	17.13 KB
CsQuery	a[href]	335.407 μs	38.2870 μs	2.0986 μs	346.6797	-	-	266.64 KB
AngleSharp	a[href]	344.184 μs	9.6133 μs	0.5269 μs	27.3438	-	-	21.21 KB
CsQuery	a[href][lang][class]	424.967 μs	22.9636 μs	1.2587 μs	454.1016	-	-	349.71 KB
AngleSharp	a[href][lang][class]	331.470 μs	37.9205 μs	2.0786 μs	21.9727	-	-	17.25 KB
CsQuery	body	3.672 μs	0.6654 μs	0.0365 μs	4.5700	-	-	3.51 KB
AngleSharp	body	313.239 μs	27.4278 μs	1.5034 μs	21.4844	-	-	16.91 KB
CsQuery	body div	28.863 μs	3.9254 μs	0.2152 μs	28.3813	-	-	21.83 KB
AngleSharp	body div	334.852 μs	21.7180 μs	1.1904 μs	32.2266	-	-	25.01 KB
CsQuery	div	20.936 μs	2.8753 μs	0.1576 μs	20.3857	-	-	15.67 KB
AngleSharp	div	333.623 μs	12.5988 μs	0.6906 μs	22.9492	-	-	17.92 KB
CsQuery	div #title	81.408 μs	0.8466 μs	0.0464 μs	78.9795	-	-	60.67 KB
AngleSharp	div #title	330.792 μs	45.5623 μs	2.4974 μs	22.4609	-	-	17.33 KB
CsQuery	div + p	58.216 μs	3.6349 μs	0.1992 μs	54.5654	-	-	41.92 KB
AngleSharp	div + p	420.089 μs	53.8564 μs	2.9521 μs	42.4805	-	-	32.99 KB
CsQuery	div > p	167.408 μs	0.7517 μs	0.0412 μs	139.6484	-	-	107.47 KB
AngleSharp	div > p	355.433 μs	198.0923 μs	10.8581 μs	47.3633	-	-	36.54 KB
CsQuery	div > p > a	359.735 μs	16.1910 μs	0.8875 μs	308.1055	-	-	236.69 KB
AngleSharp	div > p > a	347.709 μs	52.0621 μs	2.8537 μs	45.4102	-	-	35.02 KB
CsQuery	div p	163.559 μs	1.0895 μs	0.0597 μs	141.3574	-	-	108.61 KB
AngleSharp	div p	377.680 μs	22.3904 μs	1.2273 μs	84.4727	-	-	64.98 KB
CsQuery	div p a	366.239 μs	15.9706 μs	0.8754 μs	317.8711	-	-	244.52 KB
AngleSharp	div p a	437.168 μs	30.2473 μs	1.6580 μs	106.4453	-	-	82.09 KB
CsQuery	div ~ p	5,177.381 μs	205.7935 μs	11.2802 μs	6203.1250	-	-	4769.67 KB
AngleSharp	div ~ p	1,895.874 μs	435.0403 μs	23.8460 μs	957.0313	-	-	736.77 KB
CsQuery	div, p, a	380.255 μs	33.9667 μs	1.8618 μs	172.8516	18.5547	-	170.5 KB
AngleSharp	div, p, a	365.555 μs	37.8889 μs	2.0768 μs	43.4570	-	-	33.48 KB
CsQuery	div.example	58.140 μs	6.4138 μs	0.3516 μs	66.5283	-	-	51.14 KB
AngleSharp	div.example	342.246 μs	3.7113 μs	0.2034 μs	23.4375	-	-	18.11 KB
CsQuery	div.e(...).note [21]	98.881 μs	4.8513 μs	0.2659 μs	110.4736	-	-	84.91 KB
AngleSharp	div.e(...).note [21]	347.342 μs	40.8616 μs	2.2398 μs	23.4375	-	-	18.52 KB
CsQuery	div:not(.example)	44.816 μs	0.7542 μs	0.0413 μs	34.9121	-	-	26.83 KB
AngleSharp	div:not(.example)	322.179 μs	10.9380 μs	0.5995 μs	22.4609	-	-	17.59 KB
CsQuery	div[class!=made_up]	45.888 μs	12.9403 μs	0.7093 μs	49.8657	-	-	38.35 KB
AngleSharp	div[class!=made_up]	312.672 μs	2.2162 μs	0.1215 μs	23.4375	-	-	18.21 KB
CsQuery	div[class$=mple]	83.416 μs	5.0121 μs	0.2747 μs	97.6563	-	-	75.09 KB
AngleSharp	div[class$=mple]	320.199 μs	4.9361 μs	0.2706 μs	23.4375	-	-	18.21 KB
CsQuery	div[class=e]*	84.710 μs	8.6005 μs	0.4714 μs	95.9473	-	-	73.76 KB
AngleSharp	div[class*=e]	313.320 μs	11.9783 μs	0.6566 μs	23.4375	-	-	18.21 KB
CsQuery	div[class=example]	83.916 μs	2.8985 μs	0.1589 μs	95.5811	-	-	73.45 KB
AngleSharp	div[class=example]	316.863 μs	28.4840 μs	1.5613 μs	23.4375	-	-	18.22 KB
CsQuery	div[class]	61.271 μs	1.7982 μs	0.0986 μs	69.0918	-	-	53.14 KB
AngleSharp	div[class]	316.051 μs	14.2653 μs	0.7819 μs	23.4375	-	-	18.15 KB
CsQuery	div[class^=exa]	83.783 μs	18.9781 μs	1.0403 μs	96.9238	-	-	74.54 KB
AngleSharp	div[class^=exa]	311.789 μs	16.0779 μs	0.8813 μs	23.4375	-	-	18.21 KB
CsQuery	div[c(...)mple] [28]	135.848 μs	6.9089 μs	0.3787 μs	166.5039	-	-	128.02 KB
AngleSharp	div[c(...)mple] [28]	320.242 μs	19.4510 μs	1.0662 μs	23.4375	-	-	18.33 KB
CsQuery	**div[class	=dialog]**	80.618 μs	3.2140 μs	0.1762 μs	77.3926	-	-
AngleSharp	div[class	=dialog]	310.329 μs	13.1120 μs	0.7187 μs	21.9727	-	-
CsQuery	div[class~=example]	102.342 μs	2.3261 μs	0.1275 μs	117.5537	-	-	90.3 KB
AngleSharp	div[class~=example]	334.092 μs	10.3627 μs	0.5680 μs	46.3867	-	-	36.08 KB
CsQuery	h1#title	4.880 μs	0.2186 μs	0.0120 μs	6.7062	-	-	5.16 KB
AngleSharp	h1#title	325.145 μs	103.5076 μs	5.6736 μs	21.9727	-	-	17.11 KB
CsQuery	h1#title + div > p	8.236 μs	0.1216 μs	0.0067 μs	9.7656	-	-	7.51 KB
AngleSharp	h1#title + div > p	417.149 μs	28.1992 μs	1.5457 μs	50.2930	-	-	38.96 KB
CsQuery	h1[id(...)tors) [26]	9.698 μs	0.4063 μs	0.0223 μs	9.8114	-	-	7.55 KB
AngleSharp	h1[id(...)tors) [26]	333.738 μs	47.5316 μs	2.6054 μs	22.4609	-	-	17.7 KB
CsQuery	p:con(...)tors) [21]	383.667 μs	7.8307 μs	0.4292 μs	59.0820	-	-	45.61 KB
AngleSharp	p:con(...)tors) [21]	717.665 μs	17.4106 μs	0.9543 μs	313.4766	-	-	241.68 KB
CsQuery	p:first-child	110.793 μs	17.4810 μs	0.9582 μs	78.8574	-	-	60.62 KB
AngleSharp	p:first-child	338.089 μs	60.8125 μs	3.3333 μs	22.9492	-	-	18.11 KB
CsQuery	p:last-child	102.990 μs	39.6095 μs	2.1711 μs	66.5283	-	-	51.15 KB
AngleSharp	p:last-child	336.307 μs	17.5237 μs	0.9605 μs	22.4609	-	-	17.57 KB
CsQuery	p:nth-child(2n)	585.353 μs	15.8116 μs	0.8667 μs	166.0156	-	-	127.86 KB
AngleSharp	p:nth-child(2n)	1,202.662 μs	62.5433 μs	3.4282 μs	27.3438	-	-	21.32 KB
CsQuery	p:nth-child(2n+1)	587.156 μs	4.7381 μs	0.2597 μs	166.9922	-	-	129.01 KB
AngleSharp	p:nth-child(2n+1)	1,240.121 μs	124.2185 μs	6.8088 μs	27.3438	-	-	21.34 KB
CsQuery	p:nth-child(even)	581.644 μs	13.6114 μs	0.7461 μs	166.0156	-	-	127.88 KB
AngleSharp	p:nth-child(even)	1,250.388 μs	354.2351 μs	19.4168 μs	27.3438	-	-	21.3 KB
CsQuery	p:nth-child(n)	625.485 μs	33.0617 μs	1.8122 μs	225.5859	-	-	173.52 KB
AngleSharp	p:nth-child(n)	1,216.186 μs	82.9399 μs	4.5462 μs	31.2500	-	-	25.32 KB
CsQuery	p:nth-child(odd)	591.015 μs	208.7191 μs	11.4406 μs	166.9922	-	-	129 KB
AngleSharp	p:nth-child(odd)	1,190.050 μs	45.8750 μs	2.5146 μs	27.3438	-	-	21.3 KB
CsQuery	p:only-child	140.605 μs	16.9213 μs	0.9275 μs	102.0508	-	-	78.48 KB
AngleSharp	p:only-child	526.919 μs	29.0772 μs	1.5938 μs	21.4844	-	-	17.07 KB
CsQuery	ul .tocline2	49.207 μs	1.4457 μs	0.0792 μs	45.7153	-	-	35.13 KB
AngleSharp	ul .tocline2	335.199 μs	7.0508 μs	0.3865 μs	24.4141	-	-	19.04 KB
CsQuery	ul.toc > li.tocline2	95.223 μs	9.4951 μs	0.5205 μs	88.9893	-	-	68.44 KB
AngleSharp	ul.toc > li.tocline2	343.599 μs	32.2316 μs	1.7667 μs	23.4375	-	-	18.38 KB
CsQuery	ul.toc li.tocline2	121.851 μs	2.0593 μs	0.1129 μs	108.8867	-	-	83.7 KB
AngleSharp	ul.toc li.tocline2	341.464 μs	45.5889 μs	2.4989 μs	24.9023	-	-	19.38 KB