# NodeJS

This page describes the Optimization Pack for the component type NodeJS.

## Metrics

<table><thead><tr><th>Metric</th><th width="120">Unit</th><th width="299.3333333333333">Description</th></tr></thead><tbody><tr><td>cpu_used</td><td>CPUs</td><td>The total amount of CPUs used</td></tr><tr><td>cpu_util</td><td>percents</td><td>The average CPU utilization % across all the CPUs (i.e., how much time on average the CPUs are busy doing work)</td></tr><tr><td>memory_used</td><td>bytes</td><td>The total amount of memory used</td></tr><tr><td>memory_util</td><td>percent</td><td>The average memory utilization %</td></tr><tr><td>nodejs_gc_heap_used</td><td>bytes</td><td>GC heap used</td></tr><tr><td>nodejs_rss</td><td>bytes</td><td>Process Resident Set Size (RSS)</td></tr><tr><td>nodejs_v8_heap_total</td><td>bytes</td><td>V8 heap total</td></tr><tr><td>nodejs_v8_heap_used</td><td>bytes</td><td>V8 heap used</td></tr><tr><td>nodejs_number_active_threads</td><td>threads</td><td>Number of active threads</td></tr></tbody></table>

## Parameters

<table><thead><tr><th width="282">Parameter</th><th width="136">Type</th><th width="120">Unit</th><th width="167">Default Value</th><th width="180">Domain</th><th width="89">Restart</th><th width="343">Description</th></tr></thead><tbody><tr><td>v8_allocation_size_pretenuring</td><td>categorical</td><td></td><td><code>true</code></td><td><code>true</code>, <code>false</code></td><td>yes</td><td>Pretenure with allocation sites</td></tr><tr><td>v8_min_semi_space_size</td><td>integer</td><td>megabytes</td><td>0</td><td><code>0</code> → <code>1048576</code></td><td>yes</td><td>Min size of a semi-space, the new space consists of two semi-spaces</td></tr><tr><td>v8_min_semi_space_size</td><td>integer</td><td>megabytes</td><td>0</td><td><code>0</code> → <code>1048576</code></td><td>yes</td><td>Max size of a semi-space, the new space consists of two semi-spaces</td></tr><tr><td>v8_semi_space_grouth_factor</td><td>integer</td><td></td><td>2</td><td><code>0</code> → <code>100</code></td><td>yes</td><td>Factor by which to grow the new space</td></tr><tr><td>v8_max_old_space_size</td><td>integer</td><td>megabytes</td><td>0</td><td><code>0</code> → <code>1048576</code></td><td>yes</td><td>Max size of the old space</td></tr><tr><td>v8_max_heap_size</td><td>integer</td><td>megabytes</td><td>0</td><td><code>0</code> → <code>1048576</code></td><td>yes</td><td>Max size of the heap both max_semi_space_size and max_old_space_size take precedence. All three flags cannot be specified at the same time.</td></tr><tr><td>v8_initial_heap_size</td><td>integer</td><td>megabytes</td><td>0</td><td><code>0</code> → <code>1048576</code></td><td>yes</td><td>Initial size of the heap</td></tr><tr><td>v8_initial_old_space_size</td><td>integer</td><td>megabytes</td><td>0</td><td><code>0</code> → <code>1048576</code></td><td>yes</td><td>Initial old space size</td></tr><tr><td>v8_parallel_scavenge</td><td>categorical</td><td></td><td><code>true</code></td><td><code>true</code>, <code>false</code></td><td>yes</td><td>Parallel scavenge</td></tr><tr><td>v8_scavenge_task_trigger</td><td>integer</td><td></td><td>80</td><td><code>1</code> → <code>100</code></td><td>yes</td><td>Scavenge task trigger in percent of the current heap limit</td></tr><tr><td>v8_scavenge_separate_stack_scanning</td><td>categorical</td><td></td><td><code>false</code></td><td><code>true</code>, <code>false</code></td><td>yes</td><td>Use a separate phase for stack scanning in scavenge</td></tr><tr><td>v8_concurrent_marking</td><td>categorical</td><td></td><td><code>true</code></td><td><code>true</code>, <code>false</code></td><td>yes</td><td>Use concurrent marking</td></tr><tr><td>v8_parallel_marking</td><td>categorical</td><td></td><td><code>true</code></td><td><code>true</code>, <code>false</code></td><td>yes</td><td>Use parallel marking in atomic pause</td></tr><tr><td>v8_concurrent_sweeping</td><td>categorical</td><td></td><td><code>true</code></td><td><code>true</code>, <code>false</code></td><td>yes</td><td>Use concurrent sweeping</td></tr><tr><td>v8_heap_growing_percent</td><td>integer</td><td></td><td>0</td><td><code>0</code> → <code>99</code></td><td>yes</td><td>Specifies heap growing factor as (1 + heap_growing_percent/100)</td></tr><tr><td>v8_os_page_size</td><td>integer</td><td>kylobytes</td><td>0</td><td><code>0</code> → <code>1048576</code></td><td>yes</td><td>Override OS page size</td></tr><tr><td>v8_stack_size</td><td>integer</td><td>kylobytes</td><td>984</td><td><code>16</code> → <code>1048576</code></td><td>yes</td><td>Default size of stack region v8 is allowed to use</td></tr><tr><td>v8_single_threaded</td><td>categorical</td><td></td><td><code>false</code></td><td><code>true</code>, <code>false</code></td><td>yes</td><td>Disable the use of background tasks</td></tr><tr><td>v8_single_threaded_gc</td><td>categorical</td><td></td><td><code>false</code></td><td><code>true</code>, <code>false</code></td><td>yes</td><td>Disable the use of background gc tasks</td></tr></tbody></table>