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Posted to dev@tomcat.apache.org by Yoav Shapira <yo...@apache.org> on 2005/12/01 01:47:16 UTC
Re: directory listings
Hi,
It's an interesting patch and an interesting idea in general. I'm
impressed with the performance findings, although I haven't seen
anyone recently complaining about many concurrent directory listings
requests.
I have a couple of requests for the patch, if you don't mind some
feedback. I'd prefer a separate class for the DirectoryListingCache
or whatever you want to call it, with its CacheEntry and rendering,
encoding methods. It's kind of ugly to throw all of that into
DefaultServlet. DefaultServlet can then use the cache class. I'd
also prefer the relevant parameters (5, 1000) to be configurable, at
least via protected setter/getter methods. Finally, assuming the
above refactoring is done, I'd like a parameter from web.xml to
DefaultServlet setting whether to use the directory listing cache or
not. That way people can turn it off easily.
Yoav
On 11/30/05, Rafael H. Schloming <ra...@redhat.com> wrote:
> Hi,
>
> I've been looking into the performance problems associated with many
> concurrent requests of large directories. After doing some informal
> benchmarking I've come up with the attached patch that improves
> performance in this scenario. The patch adds a size limited Map with a 5
> second timeout for caching rendered directory listings. My tests show a
> significant performance improvement and the server no longer keels over
> from OutOfMemory exceptions at higher concurrency levels.
>
> Below are the results of the benchmarks I performed against the
> unmodified server.
>
> c | total | mean
> -------------------------------------------------------------
> 1 | 33.72985 seconds | 330.730 ms
> 10 | 12.807910 seconds | 1280.791 ms
> 20 | 12.641188 seconds | 2528.238 ms
> 30 | 12.930321 seconds | 3879.096 ms
> 40 | -- | --
> 50 | -- | --
> 60 | -- | --
> 70 | -- | --
> 80 | -- | --
> 90 | -- | --
> 100 | -- | --
>
>
> Here are the same benchmarks with the attached patch applied:
>
> c | total | mean
> -------------------------------------------------------------
> 1 | 0.949313 seconds | 9.493 ms
> 10 | 0.148746 seconds | 14.875 ms
> 20 | 0.167047 seconds | 33.409 ms
> 30 | 0.198910 seconds | 59.673 ms
> 40 | 0.202527 seconds | 81.011 ms
> 50 | 0.176821 seconds | 88.410 ms
> 60 | 0.203042 seconds | 121.825 ms
> 70 | 0.257176 seconds | 180.023 ms
> 80 | 0.283165 seconds | 226.532 ms
> 90 | 0.304787 seconds | 274.308 ms
> 100 | 0.196776 seconds | 196.776 ms
>
> c = number of concurrent requests (see the -c flag for ab)
> total = total time for benchmark to complete
> mean = the average time until each request is complete
> -- = benchmark timed out
>
> In all cases the total number of requests is 100 and the test
> directory being listed contains 2000 empty files.
>
> --
> Rafael H. Schloming <ra...@redhat.com>
>
>
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>
>
--
Yoav Shapira
System Design and Management Fellow
MIT Sloan School of Management
Cambridge, MA, USA
yoavs@computer.org / www.yoavshapira.com
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Re: directory listings
Posted by "Rafael H. Schloming" <ra...@redhat.com>.
Thanks for the feedback. I'll make the changes you suggest as soon as I
have a chance and repost the patch.
On Wed, 2005-11-30 at 19:47 -0500, Yoav Shapira wrote:
> Hi,
> It's an interesting patch and an interesting idea in general. I'm
> impressed with the performance findings, although I haven't seen
> anyone recently complaining about many concurrent directory listings
> requests.
>
> I have a couple of requests for the patch, if you don't mind some
> feedback. I'd prefer a separate class for the DirectoryListingCache
> or whatever you want to call it, with its CacheEntry and rendering,
> encoding methods. It's kind of ugly to throw all of that into
> DefaultServlet. DefaultServlet can then use the cache class. I'd
> also prefer the relevant parameters (5, 1000) to be configurable, at
> least via protected setter/getter methods. Finally, assuming the
> above refactoring is done, I'd like a parameter from web.xml to
> DefaultServlet setting whether to use the directory listing cache or
> not. That way people can turn it off easily.
>
> Yoav
--
Rafael H. Schloming <ra...@redhat.com>
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