Thanks for considering my request.
You are welcome ;-)
Regarding text/html caching, I believe Apache sends Last-modified headers to browsers by default. So when I refresh the same webpage in my browser, it will negotiate with Apache and only download the webpage if it has been modified since my last visit.
Yep, it depends whether the webpage is dynamically generated or not, today almost all websites use dynamically generated webpages, so each app should generate a Last-modified header in the HEAD request.
Regarding power consumption, if it contributes more to TuxFamily's operation fees than bandwidth consumption, then I suppose it is alright to leave things as-is.
Bandwidth consumption fees are ridiculous next to power fees.
But I wonder: gzip is a highly optimized compression algorithm, and computers are so capable (and underutilized) these days. Perhaps it would be more power-efficient to compress/decompress the data in the unused CPU cycles than to send/receive lots and lots of uncompressed data?
Well, I would have admitted that 10 years ago, nowadays computers are able to put their CPU in idle state, and even to change at which frequency they run. Computers are not underutilized, they just use power when there is a need, this is almost perfect on laptops, less on regular desktops. Although while former TTL chips used a lot of power in stable states, this is not the case for CMOS chips which only use power on states changes, yep, this is quite a way back 20 years ago ;-)
And if clients' computers are underutilized, this is clearly not the case of our servers. Compressing data on our side will add a new load on the already heavily loaded one. Based on the fact that compressing the data use a lot more power than uncompressing the data this is clearly not a good opportunity for us.
Regarding my request, I asked for compression primarily because the home pages of my software projects are large, monolithic XHTML documents. With many unique visits per month, these files consume a lot of bandwidth IMHO. mod_gzip or mod_deflate would benefit them greatly:
Well, this is quite an uncommon case on TuxFamily, almost all websites now use CMS which generate dynamic contents, and yep, we would prefer to host only static websites, but the time is over for those ;-)
Also, sending data without compressing them may allow us to do that without copying the data to user-land and without copying the compressed data back to kernel-land (sometimes called as zero-copy). Well, apache don't do that yet, but lighttpd, which is used on TuxFamily's download repositories, and other does.