| Deutsch English Français Italiano |
|
<vi0gsg$2f365$1@dont-email.me> View for Bookmarking (what is this?) Look up another Usenet article |
Path: ...!weretis.net!feeder9.news.weretis.net!news.quux.org!eternal-september.org!feeder2.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> Newsgroups: comp.lang.c++ Subject: Re: smrproxy v2 Date: Sun, 24 Nov 2024 16:37:36 -0800 Organization: A noiseless patient Spider Lines: 73 Message-ID: <vi0gsg$2f365$1@dont-email.me> References: <vequrc$2o7qc$1@dont-email.me> <vho4gs$pd3i$1@dont-email.me> <vhsuq6$1p56f$1@dont-email.me> <vi01g3$2cejo$1@dont-email.me> <vi0cak$2ebi8$1@dont-email.me> <vi0f71$2eo0n$1@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Mon, 25 Nov 2024 01:37:36 +0100 (CET) Injection-Info: dont-email.me; posting-host="752c11c3033f6dd442669f85f21b84b4"; logging-data="2591941"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+iImm1nsAKQpdn2wdPVmdCQIjSz4qKIow=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:qmABhdE1PoxZgQpXnrtBHvcQsn0= Content-Language: en-US In-Reply-To: <vi0f71$2eo0n$1@dont-email.me> Bytes: 4358 On 11/24/2024 4:09 PM, jseigh wrote: > On 11/24/24 18:19, Chris M. Thomasson wrote: >> On 11/24/2024 12:14 PM, jseigh wrote: >>> On 11/23/24 11:10, jseigh wrote: >>>> On 11/21/24 15:17, jseigh wrote: >>>>> On 10/17/24 08:10, jseigh wrote: >>>>>> I replaced the hazard pointer logic in smrproxy. It's now wait-free >>>>>> instead of mostly wait-free. The reader lock logic after loading >>>>>> the address of the reader lock object into a register is now 2 >>>>>> instructions a load followed by a store. The unlock is same >>>>>> as before, just a store. >>>>>> >>>>>> It's way faster now. >>>>>> >>>>>> It's on the feature/003 branch as a POC. I'm working on porting >>>>>> it to c++ and don't want to waste any more time on c version. >>>>>> >>>>>> No idea of it's a new algorithm. I suspect that since I use >>>>>> the term epoch that it will be claimed that it's ebr, epoch >>>>>> based reclamation, and that all ebr algorithms are equivalent. >>>>>> Though I suppose you could argue it's qsbr if I point out what >>>>>> the quiescent states are. >>>>>> >>>>> >>>>> I got a port to c++ working now. There are 5 proxy implementations >>>>> 1) smrproxy v2 >>>>> 2) arcproxy - reference counted proxy >>>>> 3) rwlock based proxy >>>>> 4) mutex based proxy >>>>> 5) an unsafe proxy with no locking >>>>> >>>>> The testcase is templated so you can use any of the >>>>> 5 proxy implementations without rewriting for each proxy >>>>> type. You can do apple to apple comparisons. I >>>>> realize that's the complete antithesis of current >>>>> programming practices but there you have it. :) >>>>> >>>>> A bit of clean up and performance tuning now. >>>>> >>>> >>>> Ok, smrproxy lock/unlock is down to 0.6 nanoseconds now, >>>> about what the C version was. >>>> >>> >>> I've been using cpu time to measure performance. That's ok >>> for lock-free/wait-free locking. For normal mutexes and >>> shared locks, it doesn't measure wait time so those didn't >>> look as bad as they really were. You can add logic >>> to measure how long it takes to acquire a lock but that >>> adds significant overhead. >> >> I remember back in the day when I was comparing and contrasting >> various lock/wait-free algorithms with their 100% lock-based counter >> parts. Some of the lock-based tests too so long that I just terminated >> the damn program. Iirc, a lock-free test would take around 5 minutes. >> The lock- based test would be around 30+ minutes. This was way back on >> c.p.t. > > I set the iteration count as a parameter. Mutex can be particularly > slow with a lot of reader threads. I usually see about 1000 - 10000 > times slower than smrproxy. rwlocks aren't as bad, about 200 x > slower. > > Mutex, rwlock, and arcproxy use interlocked instructions so you > can get a really wide performance range based on cache geometry > and processor sets you run on. Big time. My older proxy uses interlocked instructions as well. Except, it does not use any CAS instructions... :^) https://pastebin.com/raw/f71480694 Wow, back in 2010! How time goes by. Shit... ;^o