[thelist] Website speed smart practices
Benjamin Hawkes-Lewis
bhawkeslewis at googlemail.com
Sun Jan 18 17:54:37 CST 2009
On 18/1/09 20:29, Bob Meetin wrote:
> I tried many of the things Benjamin noted, but was not getting a lot of
> success in consistent improved performance. The YSlow stats talked
> improvement, but my eyes said no.
It's perhaps worth stressing that YSlow is primarily a frontend
performance diagnostic tool, rather than a performance measurement tool.
In particular:
1. The grades it provides (e.g. "A (92)") are based on matching a set
of criterion based on frontend performance best practices not a direct
measure of performance at all. Obviously, the closer you match the best
practices, the higher the second rating will be. But other factors can
totally blow away the effects of these practices - e.g. networking
problems, giant images, etc. Equally, there are also special
circumstances where what's generally best practice simply isn't appropriate.
2. To exclude the effects of network latency, you'd want to aggregate
multiple requests (ideally from multiple locales) to produce any
performance figure, especially when trying to isolate the effects of
small changes.
> I tried a couple different options with ETags, but other than a ySlow
> grade improvement I could see no noticeable load speed improvement.
Note that:
1. ETags make no difference to an uncached request.
2. If you host all your content on one server, the problems with ETags
are limited to minor increases to header size (
http://developer.yahoo.com/performance/rules.html#etags ).
> For troubleshooting problems caused by network or webserver host what
> might be recommended besides 'ping' and 'traceroute' for a Linux desktop?
SSH access to a third machine on a different network would probably be
handy. ;)
--
Benjamin Hawkes-Lewis
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