Amazon Linux

This page describes the Optimization Pack for the component type Amazon Linux.

Metrics

CPU

MetricDescription

cpu_load_avg

tasks

The system load average (i.e., the number of active tasks in the system)

cpu_num

CPUs

The number of CPUs available in the system (physical and logical)

cpu_util

percent

The average CPU utilization % across all the CPUs (i.e., how much time on average the CPUs are busy doing work)

cpu_used

CPUs

The average number of CPUs used in the system (physical and logical)

cpu_util_details

percent

The average CPU utilization % broken down by usage type and CPU number (e.g., cp1 user, cp2 system, cp3 soft-irq)

Memory

MetricDescription

mem_fault

faults/s

The number of memory faults (minor+major)

mem_fault_major

faults/s

The number of major memory faults (i.e., faults that cause disk access) per second

mem_fault_minor

faults/s

The number of minor memory faults (i.e., faults that do not cause disk access) per second

mem_swapins

pages/s

The number of memory pages swapped in per second

mem_swapouts

pages/s

The number of memory pages swapped out per second

mem_total

bytes

The total amount of installed memory

mem_used

bytes

The total amount of memory used

mem_used_nocache

bytes

The total amount of memory used without considering memory reserved for caching purposes

mem_util

percent

The memory utilization % (i.e, the % of memory used)

mem_util_details

percent

The memory utilization % (i.e., the % of memory used) broken down by usage type (e.g., active memory)

mem_util_nocache

percent

The memory utilization % (i.e., the % of memory used) without considering memory reserved for caching purposes

Disk & Filesystem

MetricDescription

disk_io_inflight_details

ops

The number of IO disk operations in progress (outstanding) broken down by disk (e.g., disk /dev/nvme01)

disk_iops

ops/s

The average number of IO disk operations per second across all disks

disk_iops_details

ops/s

The number of IO disk-write operations per second broken down by disk (e.g., disk /dev/nvme01)

disk_iops_reads

ops/s

The average number of IO disk-read operations per second across all disks

disk_iops_writes

ops/s

The average number of IO disk-write operations per second across all disks

disk_read_bytes

bytes/s

The number of bytes per second read across all disks

disk_read_bytes_details

bytes/s

The average response time of IO disk operations broken down by disk (e.g., disk C://)

disk_read_write_bytes

bytes/s

The number of bytes per second written across all disks

disk_response_time_details

seconds

The average response time of IO disk operations broken down by disk (e.g., disk C://)

disk_response_time_read

seconds

The average response time of read disk operations

disk_response_time_worst

seconds

The average response time of IO disk operations of the slowest disk

disk_response_time_write

seconds

The average response time of write on disk operations

disk_swap_used

bytes

The total amount of space used by swap disks

disk_swap_util

percent

The average space utilization % of swap disks

disk_util_details

percent

The utilization % of disk, i.e how much time a disk is busy doing work broken down by disk (e.g., disk D://)

disk_write_bytes

bytes/s

The number of bytes per second written across all disks

disk_write_bytes_details

bytes/s

The number of bytes per second written from the disks broken down by disk and type of operation (e.g., disk /dev/nvme01 and operation WRITE)

filesystem_size

bytes

The size of filesystems broken down by type and device (e.g., filesystem of type ext4 for device /dev/nvme01)

filesystem_used

bytes

The amount of space used on the filesystems broken down by type and device (e.g., filesystem of type zfs on device /dev/nvme01)

filesystem_util

percent

The space utilization % of filesystems broken down by type and device (e.g., filesystem of type overlayfs on device /dev/loop1)

Network

MetricDescription

network_in_bytes_details

bytes/s

The number of inbound network packets in bytes per second broken down by network device (e.g., wlp4s0)

network_out_bytes_details

bytes/s

The number of outbound network packets in bytes per second broken down by network device (e.g., eth01)

network_tcp_retrans

retrans/s

The number of network TCP retransmissions per second

Others

MetricDescription

os_context_switch

switches/s

The number of context switches per second

proc_blocked

processes

The number of processes blocked (e.g, for IO or swapping reasons)

Parameters

CPU

ParameterTypeUnitDefault ValueDomainRestartDescription

os_cpuSchedMinGranularity

integer

nanoseconds

1500000

300000 → 30000000

no

Minimal preemption granularity (in nanoseconds) for CPU bound tasks

os_cpuSchedWakeupGranularity

integer

nanoseconds

2000000

400000 → 40000000

no

Scheduler Wakeup Granularity (in nanoseconds)

os_CPUSchedMigrationCost

integer

nanoseconds

500000

100000 → 5000000

no

Amount of time (in nanoseconds) after the last execution that a task is considered to be "cache hot" in migration decisions. A "hot" task is less likely to be migrated to another CPU, so increasing this variable reduces task migrations

os_CPUSchedChildRunsFirst

integer

0

0, 1

no

A freshly forked child runs before the parent continues execution

os_CPUSchedLatency

integer

nanoseconds

12000000

2400000 → 240000000

no

Targeted preemption latency (in nanoseconds) for CPU bound tasks

os_CPUSchedAutogroupEnabled

integer

0

0, 1

no

Enables the Linux task auto-grouping feature, where the kernel assigns related tasks to groups and schedules them together on CPUs to achieve higher performance for some workloads

os_CPUSchedNrMigrate

integer

32

3 → 320

no

Scheduler NR Migrate

Memory

ParameterTypeUnitDefault ValueDomainRestartDescription

os_MemorySwappiness

integer

percent

60

0 → 100

no

The percentage of RAM free space for which the kernel will start swapping pages to disk

os_MemoryVmVfsCachePressure

integer

100

10 → 100

no

VFS Cache Pressure

os_MemoryVmCompactionProactiveness

integer

Determines how aggressively compaction is done in the background

os_MemoryVmMinFree

integer

67584

10240 → 1024000

no

Minimum Free Memory (in kbytes)

os_MemoryTransparentHugepageEnabled

categorical

madvise

always, never, madvise

no

Transparent Hugepage Enablement Flag

os_MemoryTransparentHugepageDefrag

categorical

madvise

always, never, defer+madvise, madvise, defer

no

Transparent Hugepage Enablement Defrag

os_MemorySwap

categorical

swapon

swapon, swapoff

no

Memory Swap

os_MemoryVmDirtyRatio

integer

20

1 → 99

no

When the dirty memory pages exceed this percentage of the total memory, processes are forced to write dirty buffers during their time slice instead of continuing to write

os_MemoryVmDirtyBackgroundRatio

integer

10

1 → 99

no

When the dirty memory pages exceed this percentage of the total memory, the kernel begins to write them asynchronously in the background

os_MemoryVmDirtyExpire

integer

centiseconds

3000

300 → 30000

no

When the dirty memory pages exceed this percentage of the total memory, processes are forced to write dirty buffers during their time slice instead of continuing to write

os_MemoryVmDirtyWriteback

integer

centiseconds

500

50 → 5000

no

Memory Dirty Writeback (in centisecs)

Network

ParameterTypeUnitDefault ValueDomainRestartDescription

os_NetworkNetCoreSomaxconn

integer

megabytes

128

12 → 8192

no

Network Max Connections

os_NetworkNetCoreNetdevMaxBacklog

integer

megabytes/s

1000

100 → 10000

no

Network Max Backlog

os_NetworkNetIpv4TcpMaxSynBacklog

integer

milliseconds

256

52 → 5120

no

Network IPV4 Max Sync Backlog

os_NetworkNetCoreNetdevBudget

integer

300

30 → 30000

no

Network Budget

os_NetworkNetCoreRmemMax

integer

212992

21299 → 2129920

no

Maximum network receive buffer size that applications can request

os_NetworkNetCoreWmemMax

integer

212992

21299 → 2129920

no

Maximum network transmit buffer size that applications can request

os_NetworkNetIpv4TcpSlowStartAfterIdle

integer

1

0, 1

no

Network Slow Start After Idle Flag

os_NetworkNetIpv4TcpFinTimeout

integer

60

6 → 600

no

Network TCP timeout

os_NetworkRfs

integer

0

0 → 131072

no

If enabled increases datacache hitrate by steering kernel processing of packets to the CPU where the application thread consuming the packet is running

Storage

ParameterTypeUnitDefault ValueDomainRestartDescription

os_StorageReadAhead

integer

kilobytes

128

0 → 4096

no

Read-ahead speeds up file access by pre-fetching data and loading it into the page cache so that it can be available earlier in memory instead of from disk

os_StorageNrRequests

integer

32

12 → 1280

no

Storage Number of Requests

os_StorageRqAffinity

integer

1

1, 2

no

Storage Requests Affinity

os_StorageNomerges

integer

0

0 → 2

no

Enables the user to disable the lookup logic involved with IO merging requests in the block layer. By default (0) all merges are enabled. With 1 only simple one-hit merges will be tried. With 2 no merge algorithms will be tried

os_StorageMaxSectorsKb

integer

kilobytes

256

32 → 256

no

The largest IO size that the OS can issue to a block device

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