| <!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" xml:lang="en" lang="en"> |
| <head> |
| <meta name="generator" content="HTML Tidy for Linux/x86 (vers 12 April 2005), see www.w3.org" /> |
| <title>Tree Text Locality of Reference Timing Test</title> |
| <meta http-equiv="Content-Type" content="text/html; charset=us-ascii" /> |
| </head> |
| <body> |
| <div id="page"> |
| <h1>Hash-Based Erase Memory-Use Test</h1> |
| <h2><a name="description" id="description">Description</a></h2> |
| <p>This test inserts a number of uniform i.i.d. integer keys |
| into a container, then erases all keys except one. It measures |
| the final size of the container.</p> |
| <p>(The test was executed with <a href="../../../../testsuite/performance/ext/pb_ds/hash_random_int_erase_mem_usage.cc"><tt>hash_random_int_erase_mem_usage.cc</tt></a> |
| 2000 2000 2100)</p> |
| <h2><a name="purpose" id="purpose">Purpose</a></h2> |
| <p>The test checks how containers adjust internally as their |
| logical size decreases (see <a href="motivation.html#assoc_ers_methods">Motivation::Associative |
| Containers::Slightly Different Methods::Methods Related to |
| Erase</a>).</p> |
| <h2><a name="results" id="results">Results</a></h2> |
| <p>Figures <a href="#NHG">NHG</a>, <a href="#NHM">NHM</a> and |
| <a href="#NHL">NHL</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>, |
| respectively.</p> |
| <div id="NHG_res_div"> |
| <div id="NHG_gcc"> |
| <div id="NHG_hash_random_int_erase_mem_usage_test"> |
| <div id="NHG_assoc"> |
| <div id="NHG_Native_456_collision-chaing_456_and_probing_456_hash_random_int_erase_test"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NHG" id="NHG"><img src="hash_random_int_erase_mem_usage_test_gcc.png" alt="no image" /></a></h6>NHG: Native, collision-chaing, and probing, hash random int erase test - <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_set_ncah- |
| <tt>std::tr1::unordered_set</tt> with <tt>cache_hash_code</tt> = <tt><b>false</b></tt></li> |
| <li> |
| gp_hash_mask_linp_exp_nea_lc_1div8_1div2_nsth_set- |
| <a href="gp_hash_table.html"><tt>gp_hash_table</tt></a> |
| with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a> |
| , <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>, and <tt>Probe_Fn</tt> = <a href="linear_probe_fn.html"><tt>linear_probe_fn</tt></a> |
| </li> |
| <li> |
| cc_hash_mod_prime_nea_lc_1div8_1div1_nsth_set- |
| <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_nsth_set- |
| <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="NHM_res_div"> |
| <div id="NHM_msvc"> |
| <div id="NHM_hash_random_int_erase_mem_usage_test"> |
| <div id="NHM_assoc"> |
| <div id="NHM_Native_456_collision-chaing_456_and_probing_456_hash_random_int_erase_test"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NHM" id="NHM"><img src="hash_random_int_erase_mem_usage_test_msvc.png" alt="no image" /></a></h6>NHM: Native, collision-chaing, and probing, hash random int erase test - <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_set_ncah- |
| <tt>stdext::hash_set</tt></li> |
| <li> |
| gp_hash_mask_linp_exp_nea_lc_1div8_1div2_nsth_set- |
| <a href="gp_hash_table.html"><tt>gp_hash_table</tt></a> |
| with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a> |
| , <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>, and <tt>Probe_Fn</tt> = <a href="linear_probe_fn.html"><tt>linear_probe_fn</tt></a> |
| </li> |
| <li> |
| cc_hash_mod_prime_nea_lc_1div8_1div1_nsth_set- |
| <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_nsth_set- |
| <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="NHM_res_div"> |
| <div id="NHM_msvc"> |
| <div id="NHM_hash_random_int_erase_mem_usage_test"> |
| <div id="NHM_assoc"> |
| <div id="NHM_Native_456_collision-chaing_456_and_probing_456_hash_random_int_erase_test"><div style="border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NHM" id="NHM"><img src="hash_random_int_erase_mem_usage_test_msvc.png" alt="no image" /></a></h6>NHM: Native, collision-chaing, and probing, hash random int erase test - <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_set_ncah- |
| <tt>stdext::hash_set</tt></li> |
| <li> |
| gp_hash_mask_linp_exp_nea_lc_1div8_1div2_nsth_set- |
| <a href="gp_hash_table.html"><tt>gp_hash_table</tt></a> |
| with <tt>Comb_Hash_Fn</tt> = <a href="direct_mask_range_hashing.html"><tt>direct_mask_range_hashing</tt></a> |
| , <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>, and <tt>Probe_Fn</tt> = <a href="linear_probe_fn.html"><tt>linear_probe_fn</tt></a> |
| </li> |
| <li> |
| cc_hash_mod_prime_nea_lc_1div8_1div1_nsth_set- |
| <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_nsth_set- |
| <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="NHL_res_div"> |
| <div id="NHL_local"> |
| <div id="NHL_hash_random_int_erase_mem_usage_test"> |
| <div id="NHL_assoc"> |
| <div id="NHL_Native_456_collision-chaing_456_and_probing_456_hash_random_int_erase_test"><div style = "border-style: dotted; border-width: 1px; border-color: lightgray"><h6 class="c1"><a name="NHL" id= "NHL"><img src="hash_random_int_erase_mem_usage_test_local.png" alt="no image" /></a></h6>NHL: Native, collision-chaing, and probing, hash random int erase test - <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>STL hash-based containers act very differently than trees in |
| this respect. When erasing numerous keys from an STL |
| associative-container, the resulting memory user varies greatly |
| depending on whether the container is tree-based or hash-based. |
| As noted in <a href="motivation.html#assoc_methods">Motivation::Choice of |
| Methods</a> , this is a fundamental consequence of the STL's |
| associative containers' interface, it is not due to a specific |
| implementation.</p> |
| <p>(See <a href="priority_queue_text_pop_mem_usage_test.html">Priority Queue |
| Text <tt>pop</tt> Memory Use Test</a> for a similar phenomenon |
| regarding priority queues.)</p> |
| </div> |
| </body> |
| </html> |
