Re: 20% performance drop on PostgreSQL 9.2 from kernel 3.5.3 to3.6-rc5 on AMD chipsets - bisected

[Borislav Petkov]

On Tue, Sep 25, 2012 at 03:17:36PM +0200, Borislav Petkov wrote:
> For example, I did some measurements a couple of days ago on Bulldozer
> of tbench with and without select_idle_sibling:

Here are updated benchmark results with your patch here:
http://marc.info/?l=linux-kernel&m=134850871822587

I think this pretty much confirms Mel's results.

tbench runs single-socket OR-B  (box has 8 cores, 4 CUs) (tbench_srv localhost), tbench default settings as in debian testing

# clients							1	2	4	8	12	16
3.6-rc6+tip/auto-latest						115.91	238.571	469.606	1865.77	1863.08	1851.46
3.6-rc6+tip/auto-latest-kill select_idle_sibling():		354.619	534.714	900.069	1969.35	1955.91	1940.84
3.6-rc6+tip/auto-latest-revert-the-revert			114.001	223.171	408.507	1771.48	1757.08	1736.12
3.6-rc7+tip/auto-latest-select_idle_sibling-lists		107.39  222.439 435.255 1659.42 1697.43 1685.92

3.6-rc6+tip/auto-latest
-----------------------
Throughput 115.91 MB/sec   1 clients  1 procs  max_latency=0.296 ms
Throughput 238.571 MB/sec  2 clients  2 procs  max_latency=1.296 ms
Throughput 469.606 MB/sec  4 clients  4 procs  max_latency=0.340 ms
Throughput 1865.77 MB/sec  8 clients  8 procs  max_latency=3.393 ms
Throughput 1863.08 MB/sec  12 clients  12 procs  max_latency=0.322 ms
Throughput 1851.46 MB/sec  16 clients  16 procs  max_latency=2.059 ms

3.6-rc6+tip/auto-latest-kill select_idle_sibling()
--------------------------------------------------
Throughput 354.619 MB/sec  1 clients  1 procs  max_latency=0.321 ms
Throughput 534.714 MB/sec  2 clients  2 procs  max_latency=2.651 ms
Throughput 900.069 MB/sec  4 clients  4 procs  max_latency=10.823 ms
Throughput 1969.35 MB/sec  8 clients  8 procs  max_latency=1.630 ms
Throughput 1955.91 MB/sec  12 clients  12 procs  max_latency=3.236 ms
Throughput 1940.84 MB/sec  16 clients  16 procs  max_latency=0.314 ms

3.6-rc6+tip/auto-latest-revert-the-revert
-----------------------------------------
Throughput 114.001 MB/sec  1 clients  1 procs  max_latency=0.352 ms
Throughput 223.171 MB/sec  2 clients  2 procs  max_latency=0.348 ms
Throughput 408.507 MB/sec  4 clients  4 procs  max_latency=0.388 ms
Throughput 1771.48 MB/sec  8 clients  8 procs  max_latency=0.280 ms
Throughput 1757.08 MB/sec  12 clients  12 procs  max_latency=3.280 ms
Throughput 1736.12 MB/sec  16 clients  16 procs  max_latency=0.333 ms

3.6-rc7+tip/auto-latest-select_idle_sibling-lists
-------------------------------------------------
Throughput 107.39 MB/sec  1 clients  1 procs  max_latency=0.372 ms
Throughput 222.439 MB/sec  2 clients  2 procs  max_latency=0.345 ms
Throughput 435.255 MB/sec  4 clients  4 procs  max_latency=0.346 ms
Throughput 1659.42 MB/sec  8 clients  8 procs  max_latency=3.497 ms
Throughput 1697.43 MB/sec  12 clients  12 procs  max_latency=3.205 ms
Throughput 1685.92 MB/sec  16 clients  16 procs  max_latency=0.331 ms

-- 
Regards/Gruss,
Boris.
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