Hey,
Some more data points. I just profiled a run of guile -c 1 from HEAD.
This is what callgrind says about which functions are taking the most
time:
cumulative self total
percent percent calls file:function
23.15 19.30 151231
ports.c:scm_getc[/opt/guile-head/lib/libguile.so.18.0.0]
16928.38 7.08 12577
read.c:scm_read_expression[/opt/guile-head/lib/libguile.so.18.0.0]
6.45 6.45 93110 ???:pthread_getspecific[/lib/libpthread-2.6.so]
6.16 6.12 372
gc-card.c:scm_i_sweep_card[/opt/guile-head/lib/libguile.so.18.0.0]
106.76 4.83 9747
inline.h:ceval[/opt/guile-head/lib/libguile.so.18.0.0]
4.12 4.11 27101
ports.c:scm_ungetc[/opt/guile-head/lib/libguile.so.18.0.0]
27.79 4.04 66030
gc-mark.c:scm_gc_mark[/opt/guile-head/lib/libguile.so.18.0.0]
23.63 3.71 14562
gc-mark.c:scm_gc_mark_dependencies[/opt/guile-head/lib/libguile.so.18.0.0]
17.20 2.93 28946
pairs.c:scm_cons[/opt/guile-head/lib/libguile.so.18.0.0]
2.68 2.22 8810
symbols.c:lookup_interned_symbol[/opt/guile-head/lib/libguile.so.18.0.0]
411.68 2.21 16758
inline.h:flush_ws[/opt/guile-head/lib/libguile.so.18.0.0]
5.80 1.91 6
weaks.c:scm_i_mark_weak_vectors_non_weaks[/opt/guile-head/lib/libguile.so.18.0.0]
2.38 1.74 2052 ???:0x0000AB30[/lib/ld-2.6.so]
1.65 1.60 19977
ports.c:scm_fill_input[/opt/guile-head/lib/libguile.so.18.0.0]
1.43 1.43 288
gc-card.c:scm_i_init_card_freelist[/opt/guile-head/lib/libguile.so.18.0.0]
24.34 1.21 151126
???:0x000DE440[/opt/guile-head/lib/libguile.so.18.0.0]
18.50 1.16 8800
symbols.x:scm_i_c_mem2symbol[/opt/guile-head/lib/libguile.so.18.0.0]
1.15 1.15 8810
hash.c:scm_string_hash[/opt/guile-head/lib/libguile.so.18.0.0]
2.60 1.10 6674
alist.c:scm_acons[/opt/guile-head/lib/libguile.so.18.0.0]
7.29 1.05 2052 ???:0x0000AFC0[/lib/ld-2.6.so]
1.02 1.02 6572 ???:pthread_mutex_lock[/lib/libpthread-2.6.so]
There are more, of course. I think that the 0x0000* functions are the
PLT entries, which callgrind on PPC doesn't know how to filter out
(apparently).
The summary of this is that we (meaning, erm, Ludovic) kicked some ass
in making the reader not create so much garbage. The biggest win now
would probably be some kind of byte compilation so that the reader can
be simpler, strings and symbols can be encoded with their lengths, etc.
Probably older hands know of good strategies; is it normal that startup
cost is 40-50% in `read'?
I still think that the TLS patch can help with the pthread_getspecific
stuff; I should profile with that patch. Later maybe.
FWIW, here's a profile of (use-modules (oop goops)):
cumulative self total
percent percent calls file:function
13.74 11.62 238008
ports.c:scm_getc[/opt/guile-head/lib/libguile.so.18.0.0]
1332.06 10.32 56710
eval.i.c:ceval[/opt/guile-head/lib/libguile.so.18.0.0]
9.31 9.31 351261 ???:pthread_getspecific[/lib/libpthread-2.6.so]
7.92 7.88 1386
gc-card.c:scm_i_sweep_card[/opt/guile-head/lib/libguile.so.18.0.0]
104.30 6.28 57497
gc-mark.c:scm_gc_mark_dependencies[/opt/guile-head/lib/libguile.so.18.0.0]
109.48 5.00 207620
gc-mark.c:scm_gc_mark[/opt/guile-head/lib/libguile.so.18.0.0]
9107.65 4.52 20827
read.c:scm_read_expression[/opt/guile-head/lib/libguile.so.18.0.0]
15.28 2.83 73045
pairs.c:scm_cons[/opt/guile-head/lib/libguile.so.18.0.0]
2.62 2.61 44968
ports.c:scm_ungetc[/opt/guile-head/lib/libguile.so.18.0.0]
6.34 2.14 15
weaks.c:scm_i_mark_weak_vectors_non_weaks[/opt/guile-head/lib/libguile.so.18.0.0]
8.65 1.79 28332
alist.c:scm_acons[/opt/guile-head/lib/libguile.so.18.0.0]
1.77 1.46 14287
symbols.c:lookup_interned_symbol[/opt/guile-head/lib/libguile.so.18.0.0]
231.59 1.35 27545
inline.h:flush_ws[/opt/guile-head/lib/libguile.so.18.0.0]
1.41 1.05 17112
hashtab.c:scm_hash_fn_get_handle[/opt/guile-head/lib/libguile.so.18.0.0]
1.05 1.01 33135
ports.c:scm_fill_input[/opt/guile-head/lib/libguile.so.18.0.0]
Reading is still probably the highest cost here, but seeing ceval so
high normally means that most of the time is spent in Scheme code.
Obviously a fair bit of garbage is being generated as well. Perhaps with
microoptimizations in scm_getc() (or avoiding calling it) and with the
TLS patch, we can lower (oop goops) load time to 1.6 levels.
Regards,
Andy.
--
http://wingolog.org/
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