Fence

Fully qualified name: cupva::Fence

Defined in cupva_host.hpp

class Fence : public cupva::StaticStorage<impl::Fence, priv::CUPVA_FENCE_SIZE, priv::CUPVA_FENCE_ALIGN>

Fence is used to synchronize between PVA programs.

Fences are used to synchronize between CUPVA Streams and with other engines. Fences may optionally include timestamps. It is recommended that Fences and timestamps are used to ensure that any assumptions made about scheduling on available PVA resources are correct. In some cases scheduling may be outside of the user’s control, for example if multiple applications are submitting work. Timestamps allow verification that scheduling order is as expected.

• Maturity: GA

Public Functions

Fence() noexcept

Construct a new uninitialized object.

Usage considerations

• Allowed context for the API call

  • Interrupt handler: No

  • Signal handler: No

  • Thread-safe: No

  • Re-entrant: No

  • Async/Sync: Sync

• Required privileges: None

• Allowed execution state

  • Initialization: Yes

  • Operational: Yes

  • Reinit/Deinit Preparation: Yes

• Maturity: GA

Pre:

None

explicit Fence(SyncObj &syncObj) noexcept

Construct a new Fence object.

Usage considerations

• Allowed context for the API call

  • Interrupt handler: No

  • Signal handler: No

  • Thread-safe: No

  • Re-entrant: No

  • Async/Sync: Sync

• Required privileges: None

• Allowed execution state

  • Initialization: Yes

  • Operational: Yes

  • Reinit/Deinit Preparation: Yes

• Maturity: GA

Parameters:

syncObj – The SyncObj the fence is using.

Pre:

None

~Fence() noexcept

Destroy the Fence object.

Usage considerations

• Allowed context for the API call

  • Interrupt handler: No

  • Signal handler: No

  • Thread-safe: No

  • Re-entrant: No

  • Async/Sync: Sync

• Required privileges: None

• Allowed execution state

  • Initialization: Yes

  • Operational: Yes

  • Reinit/Deinit Preparation: Yes

• Maturity: GA

Pre:

None

Fence(Fence &&obj) noexcept

Move constructor.

Usage considerations

• Allowed context for the API call

  • Interrupt handler: No

  • Signal handler: No

  • Thread-safe: No

  • Re-entrant: No

  • Async/Sync: Sync

• Required privileges: None

• Allowed execution state

  • Initialization: Yes

  • Operational: Yes

  • Reinit/Deinit Preparation: Yes

• Maturity: GA

Pre:

None

Fence &operator=(Fence &&obj) & noexcept

Move assignment operator.

Usage considerations

• Allowed context for the API call

  • Interrupt handler: No

  • Signal handler: No

  • Thread-safe: No

  • Re-entrant: No

  • Async/Sync: Sync

• Required privileges: None

• Allowed execution state

  • Initialization: Yes

  • Operational: Yes

  • Reinit/Deinit Preparation: Yes

• Maturity: GA

Pre:

None

Fence(const Fence &obj) noexcept

Copy constructor.

Usage considerations

• Allowed context for the API call

  • Interrupt handler: No

  • Signal handler: No

  • Thread-safe: No

  • Re-entrant: No

  • Async/Sync: Sync

• Required privileges: None

• Allowed execution state

  • Initialization: Yes

  • Operational: Yes

  • Reinit/Deinit Preparation: Yes

• Maturity: GA

Pre:

None

Fence &operator=(const Fence &obj) & noexcept

Copy assignment operator.

Usage considerations

• Allowed context for the API call

  • Interrupt handler: No

  • Signal handler: No

  • Thread-safe: No

  • Re-entrant: No

  • Async/Sync: Sync

• Required privileges: None

• Allowed execution state

  • Initialization: Yes

  • Operational: Yes

  • Reinit/Deinit Preparation: Yes

• Maturity: GA

Pre:

None

bool wait(int64_t const timeout = -1) const

Block the calling thread until the fence is triggered or time out.

This API may only be called on Fences which are signaled by PVA. For externally signaled fences imported from NvSciSync, use NvSciSync APIs instead.

Usage considerations

• Allowed context for the API call

  • Interrupt handler: No

  • Signal handler: No

  • Thread-safe: Yes

  • Re-entrant: No

  • Async/Sync: Sync

• Required privileges: None

• Allowed execution state

  • Initialization: Yes

  • Operational: Yes

  • Reinit/Deinit Preparation: Yes

• Maturity: GA

Parameters:

timeout – The maximum time to wait in micro seconds. -1 will wait forever.

Throws:

cupva::Exception(DriverAPIError) – The PVA driver returned an unexpected error.

Returns:

true if wait was successful; false if timeout occurred before the fence was triggered

Pre:

None

uint64_t timestamp() const

Gets the time at which current fence expired (in nanoseconds).

Epoch is implementation defined.

Usage considerations

• Allowed context for the API call

  • Interrupt handler: No

  • Signal handler: No

  • Thread-safe: Yes

  • Re-entrant: No

  • Async/Sync: Sync

• Required privileges: None

• Allowed execution state

  • Initialization: Yes

  • Operational: Yes

  • Reinit/Deinit Preparation: Yes

• Maturity: GA

Throws:

cupva::Exception(DriverAPIError) – The PVA driver returned an unexpected error.

Pre:

cupva::Fence::wait() must return with success prior to calling this API or the timestamp value cannot be considered valid.

Returns:

the time at which current fence expired (in nanoseconds).