Amazon Linux 2
This page describes the Optimization Pack for the component type Amazon Linux 2.
Metrics
CPU
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
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
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
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
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
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
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
20
0 → 100
Determines how aggressively compaction is done in the background
os_MemoryVmPageLockUnfairness
integer
5
0 → 1000
no
Set the level of unfairness in the page lock queue.
os_MemoryVmWatermarkScaleFactor
integer
10
0 → 1000
no
The amount of memory, expressed as fractions of 10'000, left in a node/system before kswapd is woken up and how much memory needs to be free before kswapd goes back to sleep
os_MemoryVmWatermarkBoostFactor
integer
15000
0 → 30000
no
The level of reclaim when the memory is being fragmented, expressed as fractions of 10'000 of a zone's high watermark
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
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
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_StorageQueueScheduler
integer
none
none, kyber, mq-deadline, bfq
no
Storage Queue Scheduler Type
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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