Yup, good analysis, good numbers, thanks for running those. I'm happy with those results and think we should proceed.
On Thursday, 11 January 2018 05:11:56 UTC+11, Adam Johnson wrote: > > Grant, you're a star. I think the tradeoff is acceptable too. > > On 10 January 2018 at 17:05, Grant Jenks <grant...@gmail.com <javascript:> > > wrote: > >> I was able to run the more extensive benchmarks under no-contention and >> high-contention scenarios with measurements at the 50th, 90th, 99th, and >> 100th percentiles. I updated the ticket at >> https://code.djangoproject.com/ticket/28977 with the results. >> >> Under high-contention scenarios, the RWLock did serve a purpose, albeit a >> rather limited one. There's a small tradeoff to be had but I think it's >> easy to accept. Note that the benchmark does not include a miss-rate >> penalty which the LRU-eviction policy will almost certainly improve >> compared with the current random-eviction policy. >> >> Grant >> >> >> On Mon, Jan 8, 2018 at 2:25 PM, Josh Smeaton <josh.s...@gmail.com >> <javascript:>> wrote: >> >>> Nice to meet you too. Your benchmarking code was extremely handy when I >>> was profiling lru-cache-backend, so thank you! >>> >>> Are you able to run the same benchmarks using this version of the cache >>> to see how it performs in low/medium/high eviction scenarios? I think those >>> benchmarks will be nicer than the simpler cache.get() ones you have on the >>> ticket. >>> >>> I'll get to reviewing that change some time this week regardless. >>> >>> >>> >>> >>> On Tuesday, 9 January 2018 08:58:55 UTC+11, Grant Jenks wrote: >>>> >>>> Josh, it's nice to meet you here. I cited your django-lrucache-backend >>>> project in the original post of the Trac ticket. I'm also the author of >>>> DiskCache http://www.grantjenks.com/docs/diskcache/ which your project >>>> refs for benchmarks :) I added some benchmark data to the Trac ticket >>>> which >>>> may interest you. >>>> >>>> Thank you, Josh and Adam, for the +1's. I've summarized the feedback >>>> and updated the ticket at https://code.djangoproject.com/ticket/28977 >>>> It's now marked as Accepted and Has patch. I've created a pull request at >>>> https://github.com/django/django/pull/9555 Please review when able. >>>> >>>> Grant >>>> >>>> Ps. As always the docs are excellent. Even the docs for contributing >>>> are extremely helpful! >>>> >>>> >>>> On Friday, January 5, 2018 at 1:46:38 PM UTC-8, Adam Johnson wrote: >>>>> >>>>> I'm +1 for moving to LRU too, the eviction algorithm has always looked >>>>> weird to me. And Josh's library shows there are valid uses of local >>>>> memory >>>>> caching in applications - perhaps moreso these days than when Django >>>>> added >>>>> caching and memcached was the latest thing. >>>>> >>>>> >>>>>> You can also get a very nice bump in throughput if you eliminate the >>>>>> `validate_key` check >>>>> >>>>> >>>>> +1 to adding an option to disable the check as well. If you're using a >>>>> LocMemCache in production, you probably don't care about compatibility >>>>> with >>>>> memcached, because you'll be using it for different types of data. >>>>> >>>>> On 5 January 2018 at 02:53, Josh Smeaton <josh.s...@gmail.com> wrote: >>>>> >>>>>> To lend some weight to this, I've implemented an LRU loc mem cache >>>>>> and have done some benchmarking. There are some graphs in the readme: >>>>>> https://github.com/kogan/django-lrucache-backend - which I've >>>>>> written a little about >>>>>> https://devblog.kogan.com/blog/a-smarter-local-memory-django-cache-backend >>>>>> >>>>>> (I don't think my particular implementation is useful to core, as it >>>>>> relies >>>>>> on a 3rd party C lib, but using OrderedDict is cool!). >>>>>> >>>>>> You can also get a very nice bump in throughput if you eliminate the >>>>>> `validate_key` check, which does a character by character check of the >>>>>> key >>>>>> to avoid issues with particular characters in memcache. >>>>>> >>>>>> We don't want to be promoting locmemcache too much, but that said, if >>>>>> we can provide a better default then we should in my opinion. >>>>>> >>>>>> On Friday, 5 January 2018 10:12:39 UTC+11, Grant Jenks wrote: >>>>>>> >>>>>>> Hi all-- >>>>>>> >>>>>>> Long time user, first time poster, here. Thank you all for Django! >>>>>>> >>>>>>> The current local memory cache (locmem) in Django uses a >>>>>>> pseudo-random culling strategy. Rather than random, the OrderedDict >>>>>>> data >>>>>>> type can be used to implement an LRU eviction policy. A prototype >>>>>>> implementation is already used by functools.lru_cache and Python 3 now >>>>>>> supports OrderedDict.move_to_end and OrderedDict.popitem to ease the >>>>>>> implementation. >>>>>>> >>>>>>> I have created an example set of changes at >>>>>>> https://github.com/grantjenks/django/tree/ticket_28977 in commit >>>>>>> https://github.com/grantjenks/django/commit/b06574f6713d4b7d367d7a11e0268fb62f5fd1d1 >>>>>>> >>>>>>> Is there a consensus as to the value of these changes? >>>>>>> >>>>>>> Sincerely, >>>>>>> Grant Jenks >>>>>>> >>>>>>> -- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "Django developers (Contributions to Django itself)" group. >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>> send an email to django-develop...@googlegroups.com. >>>>>> To post to this group, send email to django-d...@googlegroups.com. >>>>>> Visit this group at https://groups.google.com/group/django-developers >>>>>> . >>>>>> To view this discussion on the web visit >>>>>> https://groups.google.com/d/msgid/django-developers/fdb91901-c378-4258-9201-d24a9f5f103e%40googlegroups.com >>>>>> >>>>>> <https://groups.google.com/d/msgid/django-developers/fdb91901-c378-4258-9201-d24a9f5f103e%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>> . >>>>>> >>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Adam >>>>> >>>> -- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "Django developers (Contributions to Django itself)" group. >>> To unsubscribe from this topic, visit >>> https://groups.google.com/d/topic/django-developers/Gz2XqtoYmNk/unsubscribe >>> . >>> To unsubscribe from this group and all its topics, send an email to >>> django-develop...@googlegroups.com <javascript:>. >>> To post to this group, send email to django-d...@googlegroups.com >>> <javascript:>. >>> Visit this group at https://groups.google.com/group/django-developers. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/django-developers/933c2a3e-896d-45c8-a1a9-17ef8abf42c5%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/django-developers/933c2a3e-896d-45c8-a1a9-17ef8abf42c5%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Django developers (Contributions to Django itself)" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to django-develop...@googlegroups.com <javascript:>. >> To post to this group, send email to django-d...@googlegroups.com >> <javascript:>. >> Visit this group at https://groups.google.com/group/django-developers. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/django-developers/CAG0JsGw%3DdFr33sTp93JuEHBBbLnjYfO0w5kG4%3Dnab58F7Omcsg%40mail.gmail.com >> >> <https://groups.google.com/d/msgid/django-developers/CAG0JsGw%3DdFr33sTp93JuEHBBbLnjYfO0w5kG4%3Dnab58F7Omcsg%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Adam > -- You received this message because you are subscribed to the Google Groups "Django developers (Contributions to Django itself)" group. 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