[whatwg] Limit on number of parallel Workers.

Michael Nordman michaeln at google.com
Wed Jul 8 10:59:16 PDT 2009

> This type of UA-specific setting is something best left outside the spec

On Wed, Jul 8, 2009 at 10:08 AM, Drew Wilson <atwilson at google.com> wrote:

> I think Ian's decision to add no language to the spec is the correct one.
> To be clear, we were never asking for Ian to put a limit in the spec -
> rather, given the de facto existence of limits on some platforms, we wanted
> to discuss how those platforms should behave to ensure that they were still
> compliant with the specification.
> Per previous discussions, some implementations have little or no overhead
> per worker (e.g. Firefox which uses a static thread pool to service worker
> tasks). On those platforms, it makes no sense to allow the user to specify a
> maximum number of workers, so having language in the spec saying that UAs
> "SHOULD" do so is inappropriate.
> This type of UA-specific setting is something best left outside the spec
> entirely.
> -atw
> On Wed, Jul 8, 2009 at 3:41 AM, Eduard Pascual <herenvardo at gmail.com>wrote:
>> On Wed, Jul 8, 2009 at 1:59 AM, Ian Hickson<ian at hixie.ch> wrote:
>> >
>> > I include below, for the record, a set of e-mails on the topic of
>> settings
>> > limits on Workers to avoid DOS attacks.
>> >
>> > As with other such topics, the HTML5 spec allows more or less any
>> > arbitrary behaviour in the face of hardware limitations. There are a
>> > variety of different implementations strategies, and these will vary
>> > based on the target hardware. How to handle a million new workers will
>> be
>> > different on a system with a million cores and little memory than a
>> system
>> > with one core but terabytes of memory, or a system with 100 slow cores
>> vs
>> > a system with 10 fast cores.
>> >
>> > I have therefore not added any text to the spec on the matter. Please
>> let
>> > me know if you think there should really be something in the spec on
>> this.
>> >
>> Shouldn't a per-user setting be the sanest approach for the worker
>> limit? For example, it would quite make sense for me to want a low
>> limit (let's say 10 or so) workers on my laptop's browser; but have no
>> restriction (or a much higher one, like some thousand workers) on my
>> workstation.
>> Ian's point is key here: what's an appropriate limit for workers
>> depends almost entirely on hardware resources (and probably also on
>> implementation efficiency and other secondary aspects), and there is a
>> *huge* variety of hardware configurations that act as web clients, so
>> it's just impossible to hardcode a limit in the spec that works
>> properly for more than a minority. At most, I would suggest a note
>> like this in the spec "User agents SHOULD provide the user a way to
>> limit the ammount of workers running at a time.": emphasis on the
>> "SHOULD" rather than a "MUST", and also on the fact that the final
>> choice is for users to make. Then it'd be up to each implementor to
>> decide on default, out-of-the-box limits for their browser (it would
>> make sense, for example, if Chromium had a lower default limit than
>> FF, since C's workers are more "expensive").
>> Just my two cents.
>> Regards,
>> Eduard Pascual
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.whatwg.org/pipermail/whatwg-whatwg.org/attachments/20090708/6eced23c/attachment-0001.htm>

More information about the whatwg mailing list