Re: 60 core performance with 9.3 - Mailing list pgsql-performance
| From | Mark Kirkwood |
|---|---|
| Subject | Re: 60 core performance with 9.3 |
| Date | |
| Msg-id | 53C711B6.5040802@catalyst.net.nz Whole thread Raw |
| In response to | Re: 60 core performance with 9.3 (Andres Freund <andres@2ndquadrant.com>) |
| Responses |
Re: 60 core performance with 9.3
|
| List | pgsql-performance |
On 11/07/14 20:22, Andres Freund wrote: > On 2014-07-11 12:40:15 +1200, Mark Kirkwood wrote: >> Full report http://paste.ubuntu.com/7777886/ > >> # >> 8.82% postgres [kernel.kallsyms] [k] >> _raw_spin_lock_irqsave >> | >> --- _raw_spin_lock_irqsave >> | >> |--75.69%-- pagevec_lru_move_fn >> | __lru_cache_add >> | lru_cache_add >> | putback_lru_page >> | migrate_pages >> | migrate_misplaced_page >> | do_numa_page >> | handle_mm_fault >> | __do_page_fault >> | do_page_fault >> | page_fault > > So, the majority of the time is spent in numa page migration. Can you > disable numa_balancing? I'm not sure if your kernel version does that at > runtime or whether you need to reboot. > The kernel.numa_balancing sysctl might work. Otherwise you probably need > to boot with numa_balancing=0. > > It'd also be worthwhile to test this with numactl --interleave. > Trying out with numa_balancing=0 seemed to get essentially the same performance. Similarly wrapping postgres startup with --interleave. All this made me want to try with numa *really* disabled. So rebooted the box with "numa=off" appended to the kernel cmdline. Somewhat surprisingly (to me anyway), the numbers were essentially identical. The profile, however is quite different: Full report at http://paste.ubuntu.com/7806285/ 4.56% postgres [kernel.kallsyms] [k] _raw_spin_lock_irqsave | --- _raw_spin_lock_irqsave | |--41.89%-- try_to_wake_up | | | |--96.12%-- default_wake_function | | | | | |--99.96%-- pollwake | | | __wake_up_common | | | __wake_up_sync_key | | | sock_def_readable | | | | | | | |--99.94%-- unix_stream_sendmsg | | | | sock_sendmsg | | | | SYSC_sendto | | | | sys_sendto | | | | tracesys | | | | __libc_send | | | | pq_flush | | | | ReadyForQuery | | | | PostgresMain | | | | ServerLoop | | | | PostmasterMain | | | | main | | | | __libc_start_main | | | --0.06%-- [...] | | --0.04%-- [...] | | | |--2.87%-- wake_up_process | | | | | |--95.71%-- wake_up_sem_queue_do | | | SYSC_semtimedop | | | sys_semop | | | tracesys | | | __GI___semop | | | | | | | |--99.75%-- LWLockRelease | | | | | | | | | |--25.09%-- RecordTransactionCommit | | | | | CommitTransaction | | | | | CommitTransactionCommand | | | | | finish_xact_command.part.4 | | | | | PostgresMain | | | | | ServerLoop | | | | | PostmasterMain | | | | | main | | | | | __libc_start_main regards Mark
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