#8224: Excessive system time -- new IO manager problem? -------------------------------------+------------------------------------- Reporter: rrnewton | Owner: Type: bug | Status: new Priority: high | Milestone: 7.8.1 Component: Runtime System | Version: 7.7 Resolution: | Keywords: IO Manager, Operating System: Linux | System Time Type of failure: Runtime | Architecture: x86_64 (amd64) performance bug | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------- Comment (by AndreasVoellmy): I also see the 200ms system time for excessive_system.hs when I run it with -N32 (and compiled with recent HEAD). Below is the first few entries after running perf record; it looks like it may be GC related. I don't see any IO manager related entries in the list. {{{ 39.02% excessive_syste excessive_system [.] gcWorkerThread 15.53% excessive_syste [kernel.kallsyms] [k] __ticket_spin_lock 6.10% excessive_syste [kernel.kallsyms] [k] default_send_IPI_mask_sequence_phys 5.88% excessive_syste excessive_system [.] allocBlock_sync 3.95% excessive_syste [kernel.kallsyms] [k] update_sd_lb_stats 2.76% excessive_syste excessive_system [.] steal_todo_block 2.18% excessive_syste [kernel.kallsyms] [k] native_write_msr_safe 1.65% excessive_syste libc-2.15.so [.] 0x7e21f 1.52% excessive_syste excessive_system [.] evacuate 0.75% excessive_syste [kernel.kallsyms] [k] dequeue_task_fair 0.74% excessive_syste [kernel.kallsyms] [k] do_mmap_pgoff 0.67% excessive_syste libc-2.15.so [.] __clone 0.67% excessive_syste [kernel.kallsyms] [k] memset 0.66% excessive_syste [kernel.kallsyms] [k] dequeue_entity 0.66% excessive_syste [kernel.kallsyms] [k] release_pages 0.62% excessive_syste [kernel.kallsyms] [k] find_next_bit 0.58% excessive_syste excessive_system [.] scavenge_until_all_done 0.56% excessive_syste [kernel.kallsyms] [k] __schedule 0.54% excessive_syste [kernel.kallsyms] [k] hrtimer_interrupt }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8224#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler