mirror of
https://github.com/tinygo-org/tinygo.git
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Ayke van Laethem
60f8a62978
This commit adds support for a scheduler that runs a scheduler on all available cores. It is meant to be used on baremetal systems with a fixed number of cores, such as the RP2040. The initial implementation adds support for multicore scheduling to the riscv-qemu target as a convenient testing target. This means that this new multicore scheduler is tested in CI, including a bunch of standard library tests (`make tinygo-test-baremetal`). This should ensure the new scheduler is reasonably well tested before trying to use it on harder-to-debug targets like the RP2040.
65 lines
1.4 KiB
Go
65 lines
1.4 KiB
Go
//go:build scheduler.cores
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package task
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import "runtime/interrupt"
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// A futex is a way for userspace to wait with the pointer as the key, and for
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// another thread to wake one or all waiting threads keyed on the same pointer.
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//
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// A futex does not change the underlying value, it only reads it before to prevent
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// lost wake-ups.
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type Futex struct {
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Uint32
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waiters Stack
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}
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// Atomically check for cmp to still be equal to the futex value and if so, go
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// to sleep. Return true if we were definitely awoken by a call to Wake or
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// WakeAll, and false if we can't be sure of that.
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func (f *Futex) Wait(cmp uint32) (awoken bool) {
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mask := lockFutex()
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if f.Uint32.Load() != cmp {
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unlockFutex(mask)
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return false
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}
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// Push the current goroutine onto the waiter stack.
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f.waiters.Push(Current())
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unlockFutex(mask)
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// Pause until this task is awoken by Wake/WakeAll.
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Pause()
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// We were awoken by a call to Wake or WakeAll. There is no chance for
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// spurious wakeups.
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return true
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}
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// Wake a single waiter.
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func (f *Futex) Wake() {
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mask := lockFutex()
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if t := f.waiters.Pop(); t != nil {
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scheduleTask(t)
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}
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unlockFutex(mask)
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}
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// Wake all waiters.
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func (f *Futex) WakeAll() {
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mask := lockFutex()
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for t := f.waiters.Pop(); t != nil; t = f.waiters.Pop() {
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scheduleTask(t)
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}
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unlockFutex(mask)
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}
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//go:linkname lockFutex runtime.lockFutex
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func lockFutex() interrupt.State
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//go:linkname unlockFutex runtime.unlockFutex
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func unlockFutex(interrupt.State)
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