Control.Concurrent.CGroup

This module provides a container-/cgroup-aware substitute for GHC's RTS -N flag. See initRTSThreads.

Documentation

initRTSThreads :: IO ()

A container-/cgroup-aware substitute for GHC's RTS -N flag.

On most platforms, this sets the number of runtime threads to match the number of physical processors (see getNumProcessors), which is the default behavior of the GHC -N flag.

When running within a cgroup on linux (most often within a container), this observes the current process' cgroup cpu quota to constrain the number of runtime threads.

By default, the number of capabilities is determined by rounding the CPU quota down.

See CPUQuota

initRTSThreadsWith :: RoundQuota -> IO ()

Same as initRTSThreads but lets you specify the quota round mode.

data RoundQuota

CPU quotas can be fractions, but the number of RTS capabilities is an integer. This type determines how to round the CPU quota to get to the number of capabilities.

The names correspond to the similarly named methods of RealFrac.

Constructors

CeilingQuota

FloorQuota

RoundQuota

Instances

Read RoundQuota

Defined in Control.Concurrent.CGroup

Methods

readsPrec :: Int -> ReadS RoundQuota

readList :: ReadS [RoundQuota]

readPrec :: ReadPrec RoundQuota

readListPrec :: ReadPrec [RoundQuota]

Show RoundQuota

Defined in Control.Concurrent.CGroup

Methods

showsPrec :: Int -> RoundQuota -> ShowS

show :: RoundQuota -> String

showList :: [RoundQuota] -> ShowS

Eq RoundQuota

Defined in Control.Concurrent.CGroup

Methods

(==) :: RoundQuota -> RoundQuota -> Bool

(/=) :: RoundQuota -> RoundQuota -> Bool

Ord RoundQuota

Defined in Control.Concurrent.CGroup

Methods

compare :: RoundQuota -> RoundQuota -> Ordering

(<) :: RoundQuota -> RoundQuota -> Bool

(<=) :: RoundQuota -> RoundQuota -> Bool

(>) :: RoundQuota -> RoundQuota -> Bool

(>=) :: RoundQuota -> RoundQuota -> Bool

max :: RoundQuota -> RoundQuota -> RoundQuota

min :: RoundQuota -> RoundQuota -> RoundQuota