Re: Wait free LW_SHARED acquisition - Mailing list pgsql-hackers

--On 30. September 2013 19:00:06 +0200 Andres Freund 
<andres@2ndquadrant.com> wrote:

>> HEAD (default):
>>
>> tps = 181738.607247 (including connections establishing)
>> tps = 182665.993063 (excluding connections establishing)
>>
>> HEAD (padding + 16 partitions + your lwlocks patch applied):
>>
>> tps = 269328.259833 (including connections establishing)
>> tps = 270685.666091 (excluding connections establishing)
>>
>> So, still an improvement but far away from what you got. Do you have some
>> other tweaks in your setup?
>
> The only relevant setting changed was -c shared_buffers=1GB, no other
> patches applied. At which scale did you pgbench -i?

I've used a scale factor of 10 (i recall you've mentioned using the same 
upthread...).

Okay, i've used 2GB shared buffers, repeating with your setting i get a far 
more noticable speedup:

tps = 346292.008580 (including connections establishing)
tps = 347997.073595 (excluding connections establishing)

Here's the perf output:

+   4.34%      207112      postgres  postgres                 [.] 
AllocSetAlloc
+   4.07%      194476      postgres  libc-2.13.so             [.] 0x127b33
+   2.59%      123471      postgres  postgres                 [.] 
SearchCatCache
+   2.49%      118974       pgbench  libc-2.13.so             [.] 0x11aaef
+   2.48%      118263      postgres  postgres                 [.] 
GetSnapshotData
+   2.46%      117646      postgres  postgres                 [.] 
base_yyparse
+   2.02%       96546      postgres  postgres                 [.] 
MemoryContextAllocZeroAligned
+   1.58%       75326      postgres  postgres                 [.] 
AllocSetFreeIndex
+   1.23%       58587      postgres  postgres                 [.] 
hash_search_with_hash_value
+   1.01%       48391      postgres  postgres                 [.] palloc
+   0.93%       44258      postgres  postgres                 [.] 
LWLockAttemptLock
+   0.91%       43575       pgbench  libc-2.13.so             [.] free
+   0.89%       42484      postgres  postgres                 [.] 
nocachegetattr
+   0.89%       42378      postgres  postgres                 [.] core_yylex
+   0.88%       42001      postgres  postgres                 [.] 
_bt_compare
+   0.84%       39997      postgres  postgres                 [.] 
expression_tree_walker
+   0.76%       36533      postgres  postgres                 [.] 
ScanKeywordLookup
+   0.74%       35515       pgbench  libc-2.13.so             [.] malloc
+   0.64%       30715      postgres  postgres                 [.] 
LWLockRelease
+   0.56%       26779      postgres  postgres                 [.] 
fmgr_isbuiltin
+   0.54%       25681       pgbench  [kernel.kallsyms]        [k] _spin_lock
+   0.48%       22836      postgres  postgres                 [.] new_list
+   0.48%       22700      postgres  postgres                 [.] hash_any
+   0.47%       22378      postgres  postgres                 [.] 
FunctionCall2Coll
+   0.46%       22095      postgres  postgres                 [.] pfree
+   0.44%       20929      postgres  postgres                 [.] palloc0
+   0.43%       20592      postgres  postgres                 [.] 
AllocSetFree
+   0.40%       19495      postgres  [unknown]                [.] 0x81cf2f
+   0.40%       19247      postgres  postgres                 [.] 
hash_uint32
+   0.38%       18227      postgres  postgres                 [.] PinBuffer
+   0.38%       18022       pgbench  [kernel.kallsyms]        [k] do_select

-- 
Thanks
Bernd