[Larceny-users] GC options

[Felix Klock]

On Jan 24, 2007, at 12:45 AM, Felix Klock wrote:

> The -reorganize-and-dump option will generate a new heap file with
> the objects partitioned into two areas: one for the codevectors, and
> another for everything else.  This can yield significant performance
> gains on IA32, because mutations to data should not affect the code
> cache after such partitioning is performed.  (I will probably have
> concrete numbers on the benefits of doing this in the next day or  
> two.)

Here are some concrete numbers illustrating the potential effects of  
using -regorganize-and-dump.

The NONDUMP column is the standard set of larceny benchmarks, running  
on a development version of the runtime.  The DUMP column is the same  
set of benchmarks, but now the benchmark compilation includes a step  
where we load the benchmark, dump the interactive heap, and then  
reorganize-and-dump the generated heap image.  Running the benchmark  
is then just a matter of loading the reorganized heap

In several cases, reorganize-and-dump yields a speed up of 5 to 20%,  
but it not an absolute win.  I'm a bit surprised by how much  
performance degrades in some cases (e.g. boyer, diviter, divrec,  
scheme); I do not have an immediate reason for it.

Anyway, the point is that Sven may want to try using -reorganize-and- 
dump, just to see if it helps.

-Felix

	"time (ms)"	"time (ms)"
	DUMP	NONDUMP
boyer	1038	676
browse	3399	3208
cpstak	1576	1911
ctak	3657	3728
dderiv	1819	2096
deriv	1332	1568
destruc	1075	1138
diviter	2023	1384
divrec	2651	1968
puzzle	1535	1475
takl	1072	1061
triangl	1954	2873
fft	1493	1698
fib	2430	2425
fibfp	3021	3324
mbrot	2679	2967
pnpoly	1761	1805
sum	385	384
sumfp	2080	2468
tak	1708	1697
ack	96	95
array1	388	416
cat	356	355
string	640	644
sum1	893	779
sumloop	508	495
tail	554	565
wc	216	222
conform	2658	2664
dynamic	1051	1039
earley	2341	2449
fibc	3758	3773
graphs	1691	1815
lattice		2208
matrix	2289	2364
maze	7589	7648
mazefun	1598	1444
nqueens	1560	1621
paraffins	4190	4370
peval	1677	1720
primes	10400	10477
ray	5024	5168
scheme	2525	1868
simplex	5911	6252
slatex	396	394
perm9	986	1075
nboyer	1871	1933
sboyer	1807	1788
gcbench	1980	2075
parsing	8738	9120
gcold	21354	25098