# Node JS 18 This page describes the Optimization Pack for the component type NodeJS. ## Metrics | Metric | Unit | Description | | ------------------------------------------- | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------- | | cpu\_used | CPUs | The total amount of CPUs used | | cpu\_util | percent | The average CPU utilization % across all the CPUs (i.e., how much time on average the CPUs are busy doing work) | | memory\_used | bytes | The total amount of memory used | | memory\_util | percent | The average memory utilization % | | nodejs\_gc\_heap\_used | bytes | GC heap used | | nodejs\_rss | bytes | Process Resident Set Size (RSS) | | nodejs\_v8\_heap\_total | bytes | V8 heap total | | nodejs\_v8\_heap\_used | bytes | V8 heap used | | nodejs\_number\_active\_threads | threads | Number of active threads | | nodejs\_suspension\_time | percent | Suspension time % | | nodejs\_active\_handles | handles | Number of active libuv handles grouped by handle type. Every handle type is C++ class name | | nodejs\_active\_handles\_total | handles | Total number of active handles | | nodejs\_active\_requests | requests | Number of active libuv requests grouped by request type. Every request type is C++ class name | | nodejs\_active\_requests\_total | requests | Total number of active requests | | nodejs\_eventloop\_lag\_max\_seconds | seconds | The maximum recorded event loop delay | | nodejs\_eventloop\_lag\_mean\_seconds | seconds | The mean of the recorded event loop delays | | nodejs\_eventloop\_lag\_min\_seconds | seconds | The minimum recorded event loop delay | | nodejs\_eventloop\_lag\_p50\_seconds | seconds | The 50th percentile of the recorded event loop delays | | nodejs\_eventloop\_lag\_p90\_seconds | seconds | The 90th percentile of the recorded event loop delays | | nodejs\_eventloop\_lag\_p99\_seconds | seconds | The 99th percentile of the recorded event loop delays | | nodejs\_eventloop\_lag\_seconds | seconds | Lag of event loop in seconds | | nodejs\_external\_memory\_bytes | bytes | NodeJS external memory size in bytes | | nodejs\_gc\_duration\_seconds\_bucket | seconds | The total count of observations for a bucket in the histogram. Garbage collection duration by kind, one of major, minor, incremental or weakcb | | nodejs\_gc\_duration\_seconds\_count | seconds | The total number of observations for Garbage collection duration by kind, one of major, minor, incremental or weakcb | | nodejs\_gc\_duration\_seconds\_sum | seconds | The total sum of observations for Garbage collection duration by kind, one of major, minor, incremental or weakcb | | nodejs\_heap\_size\_total\_bytes | bytes | Process heap size from NodeJS in bytes | | nodejs\_heap\_size\_used\_bytes | bytes | Process heap size used from NodeJS in bytes | | nodejs\_heap\_space\_size\_available\_bytes | bytes | Process heap size available from NodeJS in bytes | | nodejs\_heap\_space\_size\_total\_bytes | bytes | Process heap space size total from NodeJS in bytes | | nodejs\_heap\_space\_size\_used\_bytes | bytes | Process heap space size used from NodeJS in bytes | | process\_cpu\_seconds\_total | seconds | Total user and system CPU time spent in seconds | | process\_cpu\_system\_seconds\_total | seconds | Total system CPU time spent in seconds | | process\_cpu\_user\_seconds\_total | seconds | Total user CPU time spent in seconds | | process\_heap\_bytes | bytes | Process heap size in bytes | | process\_max\_fds | fds | Maximum number of open file descriptors | | process\_open\_fds | fds | Number of open file descriptors | | process\_resident\_memory\_bytes | bytes | Resident memory size in bytes | | process\_virtual\_memory\_bytes | bytes | Virtual memory size in bytes | ## Parameters | Parameter | Type | Unit | Default Value | Domain | restart | Description | | --------------------------------------- | ----------- | --------- | --------------------------------------- | ----------------------------------------------------------------------------------------------------------- | ------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | v8\_allocation\_size\_pretenuring | categorical | | `--allocation-site-pretenuring` | `--allocation-site-pretenuring`, `--no-allocation-site-pretenuring` | yes | Pretenure with allocation sites | | v8\_min\_semi\_space\_size | integer | megabytes | `0` | `0` → `1048576` | yes | Min size of a semi-space (in MBytes), the new space consists of two semi-spaces | | v8\_max\_semi\_space\_size | integer | megabytes | `0` | `0` → `1048576` | yes | Max size of a semi-space (in MBytes), the new space consists of two semi-spaces. This parameter is equivalent to v8\_max\_semi\_space\_size\_ordinal. | | v8\_max\_semi\_space\_size\_ordinal | ordinal | megabytes | `16` | `2`, `4`, `6`, `8`, `16`, `32`, `64`, `128`, `256`, `512`, `1024`, `2048`, `4096`, `8192`, `16384`, `32768` | yes | Max size of a semi-space (in MBytes), the new space consists of two semi-spaces. This parameter is equivalent to v8\_max\_semi\_space\_size but forces power of 2 values. | | v8\_semi\_space\_grouth\_factor | integer | | `2` | `0` → `100` | yes | Factor by which to grow the new space | | v8\_max\_old\_space\_size | integer | megabytes | `0` | `0` → `1048576` | yes | Max size of the old space (in Mbytes) | | v8\_max\_heap\_size | integer | megabytes | `0` | `0` → `1048576` | yes | Max size of the heap (in Mbytes) both max\_semi\_space\_size and max\_old\_space\_size take precedence. All three flags cannot be specified at the same time. | | v8\_initial\_heap\_size | integer | megabytes | `0` | `0` → `1048576` | yes | Initial size of the heap (in Mbytes) | | v8\_initial\_old\_space\_size | integer | megabytes | `0` | `0` → `1048576` | yes | Initial old space size (in Mbytes) | | v8\_parallel\_scavenge | categorical | | `--parallel-scavenge` | `--parallel-scavenge`, `--no-parallel-scavenge` | yes | Parallel scavenge | | v8\_scavenge\_task\_trigger | integer | | `80` | `1` → `100` | yes | Scavenge task trigger in percent of the current heap limit | | v8\_scavenge\_separate\_stack\_scanning | categorical | | `--no-scavenge-separate-stack-scanning` | `--scavenge-separate-stack-scanning`, `--no-scavenge-separate-stack-scanning` | yes | Use a separate phase for stack scanning in scavenge | | v8\_concurrent\_marking | categorical | | `--concurrent-marking` | `--concurrent-marking`, `--no-concurrent-marking` | yes | Use concurrent marking | | v8\_parallel\_marking | categorical | | `--parallel-marking` | `--parallel-marking`, `--no-parallel-marking` | yes | Use parallel marking in atomic pause | | v8\_concurrent\_sweeping | categorical | | `--concurrent-sweeping` | `--concurrent-sweeping`, `--no-concurrent-sweeping` | yes | Use concurrent sweeping | | v8\_heap\_growing\_percent | integer | | `0` | `0` → `99` | yes | Specifies heap growing factor as (1 + heap\_growing\_percent/100) | | v8\_os\_page\_size | integer | kilobytes | `0` | `0` → `1048576` | yes | Override OS page size (in KBytes) | | v8\_stack\_size | integer | kilobytes | `984` | `16` → `1048576` | yes | Default size of stack region v8 is allowed to use (in kBytes) | | v8\_single\_threaded | categorical | | `--no-single-threaded` | `--single-threaded`, `--no-single-threaded` | yes | Disable the use of background tasks | | v8\_single\_threaded\_gc | categorical | | `--no-single-threaded-gc` | `--single-threaded-gc`, `--no-single-threaded-gc` | yes | Disable the use of background gc tasks |