#10368: Armhf/Linux : test T7815 failing -------------------------------------+------------------------------------- Reporter: erikd | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.11 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: arm Type of failure: Incorrect result | Test Case: at runtime | Blocking: Blocked By: | Differential Revisions: Related Tickets: #7815 | -------------------------------------+------------------------------------- Changes (by erikd): * related: => #7815 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10368#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10368: STM test failing on Armhf/Linux -------------------------------------+------------------------------------- Reporter: erikd | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.11 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: arm Type of failure: Incorrect result | Test Case: at runtime | Blocking: Blocked By: | Differential Revisions: Related Tickets: #7815 | -------------------------------------+------------------------------------- Description changed by erikd: Old description:

During validation on armhf/linux, I found this test had failed.

Unfortunately, it only fails intermittently on one quad core Arm board and not at all on another quad core Arm board. If I do 10 runs of the test like:

{{{ for x in $(seq 1 10) ; do testsuite/tests/rts/T7815 50000 +RTS -N2 ; echo $? ; done }}}

one will fail at least 4 or 5 times and ocassionally as many as 9 or 10 times.

The two boards are:

* Inforce Computing ifc6540 with a Qualcomm Snapdragon 805 CPU. * Radxa Rock with a Rockchip RK3199 CPU.

The ifc6540 is the one that fails.

New description: During validation on armhf/linux, I found that test T7815 had failed. Unfortunately, it only fails intermittently on one quad core Arm board and not at all on another quad core Arm board. If I do 10 runs of the test like: {{{ for x in $(seq 1 10) ; do testsuite/tests/rts/T7815 50000 +RTS -N2 ; echo $? ; done }}} one will fail at least 4 or 5 times and ocassionally as many as 9 or 10 times. The two boards are: * Inforce Computing ifc6540 with a Qualcomm Snapdragon 805 CPU. * Radxa Rock with a Rockchip RK3199 CPU. The ifc6540 is the one that fails. @fryguybob suggests that this is actually a bug in the STM implementation that breaks on Arm because of Arm's weaker memory consistency model. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10368#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10368: STM test failing on Armhf/Linux -------------------------------------+------------------------------------- Reporter: erikd | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.11 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: arm Type of failure: Incorrect result | Test Case: at runtime | Blocked By: | Blocking: Related Tickets: #7815 | Differential Revisions: -------------------------------------+------------------------------------- Comment (by fryguybob): Noting here, an easier way forward is to use the coarse-grain implementation instead and make sure that the lock acquire and release of the global lock are correct for ARM. This should be good for a couple of cores. Note that an important performance bug to fix would be the one addressed here: https://github.com/fryguybob/ghc/commit/6e1df4eac2c2806b87561c5d3876ba4b50e5... -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10368#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#10368: STM test failing on Armhf/Linux -------------------------------------+------------------------------------- Reporter: erikd | Owner: Type: bug | Status: closed Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.11 Resolution: worksforme | Keywords: Operating System: Unknown/Multiple | Architecture: arm Type of failure: Incorrect result | Test Case: at runtime | Blocked By: | Blocking: Related Tickets: #7815 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: new => closed * resolution: => worksforme Comment: I also failed to reproduce this with a four-core A15 box with 7.11. Closing. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10368#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler