Re: url probability bug fix and random number use update

[Robert I. <cor...@gm...>]

Hi Val,

On Mon, Mar 8, 2010 at 7:16 AM, Val Shkolnikov <va...@nv...> wrote:

> Hi Robert,
>   There is a major bug in the curl-loader regarding use of the
> FETCH_PROBABILITY tag.  In loader_fsm.c, svn rev 574, line 1359 is
>
> cctx->url_curr_index =  (size_t) url_next;
>
> The url index is updated but not the url pointer.  The result of this bug
> is that all urls are selected regardless of the probability somewhat
> uniformly.
>
> While debugging this I also reworked the use of probability in the
> curl-loader to produce better pseudo-random numbers and also added a tag
> RANDOM_SEED that lets you control the seed.  I am attaching the patch
> against svn rev 574.  To use it
>
> cd curl-loader
> patch -p3 <curl-loader.patch.574+vs6
>

Applied the patch, thanks!

>
> I also noticed that the tag FETCH_PROBAILITY_ONCE is not used, but will let
> you decide whether it's worth to keep.
>

Please, look at the latest version in svn. Thanks!

The array of url_fetch_decision was allocated per client only, when
FETCH_PROBAILITY_ONCE was defined.
The array is used to cache the fetching decision and to decrease
the calls to random() for high-load testing.

In most of the cases, however, it will be of no use, and it was corrected
not to use url_fetch_decision array, when it is not supposed to be
allocated.


>
> Regards,
> /Val
>

Best wishes!

Robert Iakobashvili, Ph.D.
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