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diff --git a/libstdc++-v3/docs/html/ext/pb_ds/hash_text_find_find_timing_test.html b/libstdc++-v3/docs/html/ext/pb_ds/hash_text_find_find_timing_test.html new file mode 100644 index 00000000000..fafa245a93f --- /dev/null +++ b/libstdc++-v3/docs/html/ext/pb_ds/hash_text_find_find_timing_test.html @@ -0,0 +1,164 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> + +<html xmlns="http://www.w3.org/1999/xhtml"> +<head> +<meta name="generator" content="HTML Tidy for Linux/x86 (vers 12 April 2005), see www.w3.org" /> +<title>Hash Text Find Timing Test</title> +<meta http-equiv="Content-Type" content="text/html; charset=us-ascii" /> +</head> +<body> +<div id="page"> +<h1>Hash-Based Text <tt>find</tt> Find Timing Test</h1> +<h2><a name="description" id="description">Description</a></h2> +<p>This test inserts a number of values with keys from an + arbitrary text ([ <a href="references.html#wickland96thirty">wickland96thirty</a> ]) into + a container, then performs a series of finds using + <tt>find</tt> . It measures the average time for <tt>find</tt> + as a function of the number of values inserted.</p> +<p>(The test was executed with <a href="../../../../testsuite/performance/ext/pb_ds/text_find_timing.cc"><tt>text_find_timing_test</tt></a> + thirty_years_among_the_dead_preproc.txt 200 200 2100)</p> +<h2><a name="purpose" id="purpose">Purpose</a></h2> +<p>The test checks the effect of different range-hashing + functions, trigger policies, and cache-hashing policies (see + <a href="hash_based_containers.html#hash_policies">Design::Associative + Containers::Associative Containers::Hash-Based Containers::Hash + Policies</a> and <a href="hash_based_containers.html#resize_policies">Design::Associative + Containers::Hash-Based Containers::Resize Policies</a> ).</p> +<h2><a name="results" id="results">Results</a></h2> +<p>Figures <a href="#NCCG">NCCG</a>, <a href="#NCCM">NCCM</a> + and <a href="#NCCL">NCCL</a> show the results for the native + and collision-chaining types in <a href="assoc_performance_tests.html#gcc"><u>g++</u></a>, <a href="assoc_performance_tests.html#msvc"><u>msvc++</u></a>, and + <a href="assoc_performance_tests.html#local"><u>local</u></a>, + respetively.</p> +<div id="NCCG_res_div"> +<div id="NCCG_gcc"> +<div id="NCCG_text_find_timing_test_hash"> +<div id="NCCG_assoc"> +<div id="NCCG_Native_and_collision-chaining_hash_text_find_timing_test_using__tt_find_455tt_"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NCCG" id="NCCG"><img src="text_find_timing_test_hash_gcc.png" alt="no image" /></a></h6>NCCG: Native and collision-chaining hash text find timing test using <tt>find</tt> - <a href="assoc_performance_tests.html#gcc">g++</a><p>In the above figure, the names in the legends have the following meaning:</p> +<ol> +<li> +n_hash_map_ncah- +<tt>std::tr1::unordered_map</tt> with <tt>cache_hash_code</tt> = <tt><b>false</b></tt></li> +<li> +cc_hash_mod_prime_nea_lc_1div8_1div1_nsth_map- +<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> +with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a> +, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> + with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a> +, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> + with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/1</i></li> +<li> +cc_hash_mask_exp_nea_lc_1div8_1div2_sth_map- +<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> +with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a> +, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> + with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a> +, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> + with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/2</i></li> +<li> +cc_hash_mask_exp_nea_lc_1div8_1div1_nsth_map- +<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> +with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a> +, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> + with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a> +, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> + with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/1</i></li> +<li> +cc_hash_mask_exp_nea_lc_1div8_1div2_nsth_map- +<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> +with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a> +, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> + with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a> +, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> + with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/2</i></li> +</ol> +</div><div style="width: 100%; height: 20px"></div></div> +</div> +</div> +</div> +</div> +<div id="NCCM_res_div"> +<div id="NCCM_msvc"> +<div id="NCCM_text_find_timing_test_hash"> +<div id="NCCM_assoc"> +<div id="NCCM_Native_and_collision-chaining_hash_text_find_timing_test_using__tt_find_455tt_"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NCCM" id="NCCM"><img src="text_find_timing_test_hash_msvc.png" alt="no image" /></a></h6>NCCM: Native and collision-chaining hash text find timing test using <tt>find</tt> - <a href="assoc_performance_tests.html#msvc">msvc++</a><p>In the above figure, the names in the legends have the following meaning:</p> +<ol> +<li> +n_hash_map_ncah- +<tt>stdext::hash_map</tt></li> +<li> +cc_hash_mod_prime_nea_lc_1div8_1div1_nsth_map- +<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> +with <tt>Comb_Hash_Fn</tt> = <a href="direct_mod_range_hashing.html"><tt>direct_mod_range_hashing</tt></a> +, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> + with <tt>Size_Policy</tt> = <a href="hash_prime_size_policy.html"><tt>hash_prime_size_policy</tt></a> +, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> + with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/1</i></li> +<li> +cc_hash_mask_exp_nea_lc_1div8_1div1_nsth_map- +<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> +with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a> +, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> + with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a> +, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> + with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/1</i></li> +<li> +cc_hash_mask_exp_nea_lc_1div8_1div2_nsth_map- +<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> +with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a> +, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> + with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a> +, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> + with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/2</i></li> +<li> +cc_hash_mask_exp_nea_lc_1div8_1div2_sth_map- +<a href="cc_hash_table.html"><tt>cc_hash_table</tt></a> +with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a> +, and <tt>Resize_Policy</tt> = <a href="hash_standard_resize_policy.html"><tt>hash_standard_resize_policy</tt></a> + with <tt>Size_Policy</tt> = <a href="hash_exponential_size_policy.html"><tt>hash_exponential_size_policy</tt></a> +, and <tt>Trigger_Policy</tt> = <a href="hash_load_check_resize_trigger.html"><tt>hash_load_check_resize_trigger</tt></a> + with <i>α<sub>min</sub></i> = <i>1/8</i> and <i>α<sub>max</sub></i> = <i>1/2</i></li> +</ol> +</div><div style="width: 100%; height: 20px"></div></div> +</div> +</div> +</div> +</div> +<div id="NCCL_res_div"> +<div id="NCCL_local"> +<div id="NCCL_text_find_timing_test_hash"> +<div id="NCCL_assoc"> +<div id="NCCL_Native_and_collision-chaining_hash_text_find_timing_test_using__tt_find_455tt_"><div style = "border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NCCL" id= "NCCL"><img src="text_find_timing_test_hash_local.png" alt="no image" /></a></h6>NCCL: Native and collision-chaining hash text find timing test using <tt>find</tt> - <a href = "assoc_performance_tests.html#local">local</a></div><div style = "width: 100%; height: 20px"></div></div> +</div> +</div> +</div> +</div> +<h2><a name="observations" id="observations">Observations</a></h2> +<p>In this setting, the range-hashing scheme (See <a href="hash_based_containers.html#hash_policies">Design::Associative + Containers::Hash-Based Containers::Hash Policies</a> ) affects + performance more than other policies. As Figure <a href="#NCCG">NCCG</a> shows, containers using mod-based + range-hashing (including the native hash-based container, which + is currently hard-wired to this scheme) have lower performance + than those using mask-based range-hashing. A modulo-based + range-hashing scheme's main benefit is that it takes into + account all hash-value bits. Standard string hash-functions are + designed to create hash values that are nearly-uniform as is [ + <a href="references.html#knuth98sorting">knuth98sorting</a> + ].</p> +<p>Trigger policies (see <a href="hash_based_containers.html#resize_policies">Design::Associative + Containers::Hash-Based Containers::Resize Policies</a> ), + <i>i.e.</i> the load-checks constants, affect performance to a + lesser extent.</p> +<p>Perhaps surprisingly, storing the hash value alongside each + entry affects performance only marginally, at least in + <tt>pb_ds</tt> 's implementation. (Unfortunately, it was not + possible to run the tests with <tt>std::tr1::unordered_map</tt> + 's <tt>cache_hash_code = <b>true</b></tt> , as it appeared to + malfuntion.)</p> +<p><a href="assoc_performance_tests.html#hash_based_policies">Observations::Hash-Based + Containers' Policies</a> summarizes some observations on + hash-based containers' policies.</p> +</div> +</body> +</html> |