Re: Sun performance - Major discovery!

On Wed, 8 Oct 2003, Neil Conway wrote:

> Interesting (and surprising that the performance differential is that
> large, to me at least). Can you tell if the performance gain comes from
> an improvement in a particular subsystem? (i.e. could you get a profile
> of Sun/gcc and compare it with Sun/sunsoft).
>

Yeah - like I expected it was able to generate much better code for
_bt_checkkeys which was the #1 function in gcc on both sun & linux.

and as you can see, suncc was just able to generate much nicer code. I'd
look at the assembler output but that won't be useful since I am very
unfamiliar with the [ultra]sparc instruction set..

Here's the prof and gprof output for the latest run:
GCC:
% cumulative self self total
time seconds seconds calls ms/call ms/call name
31.52 19.44 19.44 internal_mcount
20.28 31.95 12.51 8199466 0.00 0.00 _bt_checkkeys
5.61 35.41 3.46 8197422 0.00 0.00 _bt_step
5.01 38.50 3.09 24738620 0.00 0.00 FunctionCall2
3.00 40.35 1.85 8194186 0.00 0.00 varchareq
2.61 41.96 1.61 24309 0.07 0.28 _bt_next
2.42 43.45 1.49 1003 1.49 1.51 AtEOXact_Buffers
2.37 44.91 1.46 12642 0.12 0.12 _read
2.33 46.35 1.44 16517771 0.00 0.00 pg_detoast_datum
2.08 47.63 1.28 8193186 0.00 0.00 int4lt
1.35 48.46 0.83 8237204 0.00 0.00 BufferGetBlockNumber
1.35 49.29 0.83 8193888 0.00 0.00 int4ge
1.35 50.12 0.83 _mcount

SunCC -pg -fast.
%Time Seconds Cumsecs #Calls msec/call Name

23.2 4.27 4.27108922056 0.0000 _mcount
20.7 3.82 8.09 8304052 0.0005 _bt_checkkeys
13.7 2.53 10.6225054788 0.0001 FunctionCall2
5.1 0.94 11.56 24002 0.0392 _bt_next
4.4 0.81 12.37 8301867 0.0001 _bt_step
3.4 0.63 13.00 8298219 0.0001 varchareq
2.7 0.50 13.5016726855 0.0000 pg_detoast_datum
2.4 0.45 13.95 8342464 0.0001 BufferGetBlockNumber
2.4 0.44 14.39 8297941 0.0001 int4ge
2.2 0.41 14.80 1003 0.409 AtEOXact_Buffers
2.0 0.37 15.17 4220349 0.0001 lc_collate_is_c
2.0 0.37 15.54 8297219 0.0000 int4lt
1.6 0.29 15.83 26537 0.0109 AllocSetContextCreate
0.9 0.16 15.99 1887 0.085 pglz_decompress
0.7 0.13 16.12 159966 0.0008 nocachegetattr
0.7 0.13 16.25 4220349 0.0000 varstr_cmp
0.6 0.11 16.36 937576 0.0001 MemoryContextAlloc
0.5 0.09 16.45 150453 0.0006 hash_search

> -Neil
>
>
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--
Jeff Trout <jeff(at)jefftrout(dot)com>
http://www.jefftrout.com/
http://www.stuarthamm.net/