Bug#750785: Slowness with context and xetex
Cold turkey!
On 14-08-11 04:06 PM, Norbert Preining wrote:
> I'll do, after I am back from holidays ;-)
>
> ------------------------------------------------------------------------
> PREINING, Norbert http://www.preining.info
> <http://www.preining.info/>
> JAIST, Japan TeX Live & Debian Developer
> GPG: 0x860CDC13 fp: F7D8 A928 26E3 16A1 9FA0 ACF0 6CAC A448 860C DC13
> ------------------------------------------------------------------------
>
> On 2014/08/12, at 0:23, Behdad Esfahbod <behdad@behdad.org
> <mailto:behdad@behdad.org>> wrote:
>
>> That certainly isn't working as intended. I tested the cache locally (not in
>> the context of XeTeX) and it works fine.
>>
>> Can you dig into hb_shape_plan_matches() and see why it's never matching?
>>
>>
>> On 14-08-11 06:01 AM, Norbert Preining wrote:
>>> Hi
>>>
>>> I think I found the bug:
>>>
>>> On Mon, 11 Aug 2014, Norbert Preining wrote:
>>>> This is about 100 times faster .... total runtime on that document, with
>>>> debug output, real 1.845s.
>>>
>>>
>>> I recompiled harfbuzz with some debug statements in the
>>> function, and it turned out that when I do that:
>>> (in src/hb-shape-plan.cc <http://hb-shape-plan.cc>, function
>>> hb_shape_plan_create_cached
>>> ...
>>> retry:
>>> fprintf(stderr, "DEBUG harfbuzz: after retry label\n");
>>> hb_face_t::plan_node_t *cached_plan_nodes = (hb_face_t::plan_node_t *)
>>> hb_atomic_ptr_get (&face->shape_plans);
>>> for (hb_face_t::plan_node_t *node = cached_plan_nodes; node; node =
>>> node->next) {
>>> fprintf(stderr, "DEBUG harfbuzz node for loop\n");
>>> if (hb_shape_plan_matches (node->shape_plan, &proposal)) {
>>> fprintf(stderr, "DEBUG harfbuzz return from node loop\n");
>>> return hb_shape_plan_reference (node->shape_plan);
>>> }
>>> }
>>> ...
>>>
>>> THat the loop is getting longer and longer and longer and longer.
>>> For each iteration it loops one more time!! I only send you
>>> the start of the log output:
>>> .....
>>> DEBUG [1407750920] <0> return from hb_shape_plan_create_cached
>>> DEBUG [1407750920] hbFace=47040112, segment_props.script=1281455214,
>>> segment_props.direction=4, segment-props.language=47792128,
>>> engine->nFeatures=0, shaperList=¨1N
>>> DEBUG harfbuzz: after retry label
>>> DEBUG harfbuzz node for loop
>>> DEBUG harfbuzz node for loop
>>> DEBUG harfbuzz: before shape_plan_create
>>> DEBUG harfbuzz: before calloc
>>> DEBUG [1407750920] <0> return from hb_shape_plan_create_cached
>>> DEBUG [1407750920] hbFace=47040112, segment_props.script=1281455214,
>>> segment_props.direction=4, segment-props.language=47792128,
>>> engine->nFeatures=0, shaperList=¨1N
>>> DEBUG harfbuzz: after retry label
>>> DEBUG harfbuzz node for loop
>>> DEBUG harfbuzz node for loop
>>> DEBUG harfbuzz node for loop
>>> DEBUG harfbuzz: before shape_plan_create
>>> DEBUG harfbuzz: before calloc
>>> DEBUG [1407750920] <0> return from hb_shape_plan_create_cached
>>> DEBUG [1407750920] hbFace=47040112, segment_props.script=1281455214,
>>> segment_props.direction=4, segment-props.language=47792128,
>>> engine->nFeatures=0, shaperList=¨1N
>>> DEBUG harfbuzz: after retry label
>>> DEBUG harfbuzz node for loop
>>> DEBUG harfbuzz node for loop
>>> DEBUG harfbuzz node for loop
>>> DEBUG harfbuzz node for loop
>>> DEBUG harfbuzz: before shape_plan_create
>>> DEBUG harfbuzz: before calloc
>>> DEBUG [1407750920] <0> return from hb_shape_plan_create_cached
>>>
>>>
>>> SO with every char another loop element is added.
>>>
>>> Still on the first page, I already had:
>>> [~/foo] grep loop xelatexslow-debug-output.log | wc -l
>>> 6249880
>>> ...
>>>
>>>
>>> That explains why it is getting soooo slow ...
>>>
>>>
>>> I cannot dig into the code now, but this is for sure not
>>> planned ;-)
>>>
>>>
>>> Norbert
>>>
>>> ------------------------------------------------------------------------
>>> PREINING, Norbert http://www.preining.info
>>> JAIST, Japan TeX Live & Debian Developer
>>> GPG: 0x860CDC13 fp: F7D8 A928 26E3 16A1 9FA0 ACF0 6CAC A448 860C DC13
>>> ------------------------------------------------------------------------
>>>
>>
>> --
>> behdad
>> http://behdad.org/
--
behdad
http://behdad.org/
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