P.S. I wonder if def-gl-thm clears hash tables. But even if it does,
I wouldn't expect it that particular form to hash a lot of strings.
-- Matt
Date: Mon, 11 Nov 2013 16:44:54 -0600
From: Matt Kaufmann <kaufm...@cs.utexas.edu>
Cc: gcl-devel@gnu.org
Hi, Jared and Camm --
I ran the experiment you suggested, Jared (thanks for the suggestion).
In books/centaur/gl/:
(ubt! 1)
(include-book "portcullis")
(rebuild "solutions.lisp" t)
(u)
(time$ (def-gl-thm 1f
:hyp (and (unsigned-byte-p 3000 x)
(unsigned-byte-p 3000 y))
:concl (equal (+ x y) (+ y x))
:g-bindings (gl::auto-bindings (:mix (:nat x 3000)
(:nat y 3000)))))
That took 78 seconds (a very nice improvement!). Then:
ACL2 !>:q
Exiting the ACL2 read-eval-print loop. To re-enter, execute (LP).
ACL2>(hons-summary)
Normed Objects Summary
- NIL-HT: 4 count, 5,000 size ( 0.08% full)
- CDR-HT: 9,071,974 count, 12,974,622 size (69.92% full)
- CDR-HT-EQL: 0 count, 1,000 size ( 0.00% full)
- STR-HT: 1 count, 1,000 size ( 0.10% full)
- PERSIST-HT: 0 count, 100 size ( 0.00% full)
- FAL-HT: 0 count, 1,000 size ( 0.00% full)
NIL
ACL2>(hl-hspace-str-ht *default-hs*)
#<hash-table 0000000004e06af0>
ACL2>
(I did some searching and did find another 'equal hash table besides
that str-ht, namely; *hcomp-book-ht*, but it's quite small and not
relevant here.)
So I'm again stumped, since the cdr-ht is, I think, an 'eq hash
table.
Camm, is there a way to identify the callers that are setting a hash
table with test 'equal? The profile you sent seems to be at the level
of C, so I don't know what to trace.
-- Matt
From: "Jared C. Davis" <ja...@cs.utexas.edu>
Date: Mon, 11 Nov 2013 16:18:24 -0600
Cc: Camm Maguire <c...@maguirefamily.org>,
"GCL-devel@gnu.org" <gcl-devel@gnu.org>
Hi,
I believe Matt is correct that the only use of EQUAL hash tables in
the (h) part of ACL2(h) is for string hashing. In fact, for the most
part, in a single-threaded context, I think there should typically be
just a single string hash table.
At the relevant part of your benchmark, you might run (hons-summary)
to see the size and count of this table, in case that's helpful. Or
if you want to get your hands on the hash table to really take a deep
look at it, you can try, e.g.,:
ACL2 !>(hons "foo" "bar")
("foo" . "bar")
ACL2 !>:q
:q
Exiting the ACL2 read-eval-print loop. To re-enter, execute (LP).
? (hl-hspace-str-ht *default-hs*)
#<HASH-TABLE :TEST EQUAL size 2/1000 #x30200EA5441D>
Cheers,
Jared
On Mon, Nov 11, 2013 at 3:21 PM, Matt Kaufmann <kaufm...@cs.utexas.edu>
wrote:
> Hi, Camm --
>
> That's interesting, but I'm confused, and I'm definitely not an expert
> on hash tables. I looked at the files that implement the "(h)" part
> of ACL2(h), which is almost certainly what is involving hash tables,
> and it looks to me like maybe the only 'equal hash tables are for
> strings.
>
> I'm forwarding this to Jared, since he is the most recent author of
> that code (plus, you mention him as helping with potentially related
> reader issues), in case he has time to shed light on this.
>
> -- Matt
> From: Camm Maguire <c...@maguirefamily.org>
> Date: Mon, 11 Nov 2013 12:49:41 -0500
>
> Greetings!
>
> Just a followup -- the remaining time appears to be in sethash for an
> 'equal hash-table:
>
>
=============================================================================
> index % time self children called name
> 103979625 sethash [1]
> [1] 84.2 2.11 49.03 0+103979625 sethash [1]
> 22.58 6.16 167566772/167566772 fShash_equal [2]
> 0.00 20.28 119656/131885 alloc_relblock [6]
> 0.01 0.00 119656/205048 alloc_object [47]
> 103979625 sethash [1]
> -----------------------------------------------
> 22.58 6.16 167566772/167566772 sethash [1]
> [2] 47.3 22.58 6.16 167566772 fShash_equal [2]
> 5.25 0.00 363849475/363849475 hash_eql [12]
> 0.91 0.00 1174935219/1174940911 eql1 [18]
> 0.00 0.00 12/2577623 Fand <cycle 2> [151]
> -----------------------------------------------
> 0.29 5.78 3/14 make_cons [9]
> 1.06 21.19 11/14 alloc_relblock [6]
> [3] 46.6 1.35 26.97 14 GBC [3]
> 26.93 0.00 25304834/25331171 sgc_mark_object1
<cycle 1> [5]
>
=============================================================================
>
> This is somewhat remarkable, as the 'eql gethash calls which greatly
> dominate in number are no longer on the radar. Presumably the
algorithm
> makes some complex cons, (definitely not your grandmother's '(1 2 3)
> list), uses an 'equal hashtable to make it equal-unique, and then
uses
> that as a key in an 'eql hashtable for the real heavy work.
>
> This just reminded me of the work we did earlier regarding the
loading
> of complex conses in compiled files, which overloaded the #= reader
> until we memoized the routine calculating the hash-equal index.
This is
> barely necessary to the gcl compiler -- the point is to catch errors
> where the constant list to be compiled in changes during compilation.
> And as I indicated earlier, we flush the memoizing hash tables on
each
> compile-file. This, together with the implementation of the
'hybrid' #=
> algorithm suggested by Jared, made the loading of these conses very
> fast.
>
> My question is if we've learned anything which might make the above
> results yet faster. By default, the hash-equal index descends no
more
> than three levels, car and cdr, into a cons to xor up the index. It
> does not attempt to descend the entire structure memoizing as one
goes
> like the compiler version. There the depth limit is much greater
(1000)
> due to its purpose and the absence of any table. My intuition tells
me
> that there is no way a memoized version of the generic hash-equal
would
> pay off. It seems we would have to flush on each call, or never. It
> would only speed up index calculations of great depth, which is only
> useful in hash tables if your index is insufficiently random at the
> default depth of 3. This does not appear the case, as #'equal
itself is
> absent from the profiling report, implying that the hit rate to the
> index is good.
>
> I suppose an 'equal hashtable could keep an 'eq hashtable internally
for
> the life of the table. That might be interesting.
>
> In any case, I don't want to waste a lot of time reinventing some
> wheel. If you or any of the other hashtable experts have some wisdom
> here, I'd be most appreciative.
>
> Take care,
> --
> Camm Maguire
c...@maguirefamily.org
>
==========================================================================
> "The earth is but one country, and mankind its citizens." --
Baha'u'llah
>
>
> _______________________________________________
> Gcl-devel mailing list
> Gcl-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/gcl-devel
--
Jared C. Davis <ja...@cs.utexas.edu>
11410 Windermere Meadows
Austin, TX 78759
http://www.cs.utexas.edu/users/jared/
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