Re: Performance degradation in commit ac1d794

​
2015-12-25 20:44 GMT+03:00 Andres Freund <andres(at)anarazel(dot)de>:

> On December 25, 2015 6:27:06 PM GMT+01:00, "Васильев Дмитрий"
> >>​If so, could you provide a hierarchical before/after profile?
> >
> >​Performance | Git hash commit | Date
> >~ 360k tps | c3e7c24a1d60dc6ad56e2a0723399f1570c54224 | Thu Nov 12
> >09:12:18
> >2015 -0500
> >~ 360k tps | ac1d7945f866b1928c2554c0f80fd52d7f977772 | Thu Nov 12
> >09:00:33 2015 -0500
> >~ 960k tps | a05dc4d7fd57d4ae084c1f0801973e5c1a1aa26e | Thu Nov 12
> >07:40:31 2015 -0500
>
> Profile as in perf oprofile or something.
>
> ---
> Please excuse brevity and formatting - I am writing this on my mobile
> phone.
>

​ac1d794​:

​ Samples: 1M of event 'cycles', Event count (approx.): 816922259995, UID:
pgpro
Overhead Shared Object Symbol

69,72% [kernel] [k] _raw_spin_lock_irqsave
1,43% postgres [.] _bt_compare
1,19% postgres [.] LWLockAcquire
0,99% postgres [.] hash_search_with_hash_value
0,61% postgres [.] PinBuffer

0,46% postgres [.] GetSnapshotData ​

​a05dc4d:​

​Samples: 1M of event 'cycles', Event count (approx.): 508150718694, UID:
pgpro
Overhead Shared Object Symbol

4,77% postgres [.] GetSnapshotData
4,30% postgres [.] _bt_compare
3,13% postgres [.] hash_search_with_hash_value
3,08% postgres [.] LWLockAcquire
2,09% postgres [.] LWLockRelease
2,03% postgres [.] PinBuffer

​Perf record ​generate big traffic:

time perf record -u pgpro -g --call-graph=dwarf
^C[ perf record: Woken up 0 times to write data ]
Warning:
Processed 1078453 events and lost 18257 chunks!
Check IO/CPU overload!
[ perf record: Captured and wrote 8507.985 MB perf.data (1055663 samples) ]
real 0m8.791s
user 0m0.678s
sys 0m8.120s

​If you want i give you ssh-access.