andersb at vgnett.no
Tue Aug 1 20:47:08 CEST 2006
On Aug 1, 2006, at 19:49, Poul-Henning Kamp wrote:
> In message <3033.193.69.165.4.1154452266.squirrel at denise.vg.no>,
> "Anders Berg"
> With the architecture I/we have chosen, prefetching will help us avoid
> the momentary pile-up that would happen when a much used document
> As far as I can tell, this is not very important to VG, but doing
> proper prefetching will improve responsetime a bit when those
> events happen.
Yes, it is not really that important for VG per se., since we can
live without it today.
We would turn it on if it was available though :)
>> 2. If we wanna use a algorithm, we would use a old one.
> I fully agree.
> My plan was to use one that said "if the document has been used
> more than 2 times in the previous incarnation, then prefetch,
> otherwise discard." for some suitable value of 2.
> Maybe a frequency is better: If document has been used more
> than once per minute in previous incarnation, then prefetch,
> otherwise discard".
Documents that take long to "make" would benefit from having the time
it takes to make it in the algorithm.
A static doc like jpeg's, costs so little deliver that the pile-up
would hardly be noticed, but you know that.
Hybrid take's that into account, but has the horrible O(log(k))...
But as you mention underneath, it's configurable :)
> Either way, the policy will be in VCL...
Ahh, that's right.
> Anyway, for now prefetching is not on the list of 1.0 things
> so it's not very important.
Okay, was unsure where we placed prefetch.
> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG | TCP/IP since RFC 956
> FreeBSD committer | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by
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