TE
科技回声
首页24小时热榜最新最佳问答展示工作
GitHubTwitter
首页

科技回声

基于 Next.js 构建的科技新闻平台,提供全球科技新闻和讨论内容。

GitHubTwitter

首页

首页最新最佳问答展示工作

资源链接

HackerNews API原版 HackerNewsNext.js

© 2025 科技回声. 版权所有。

SI Units for Request Rate

111 点作者 DaveFlater超过 1 年前

23 条评论

DaveFlater超过 1 年前
The &quot;two wrongs&quot; hostname is apt. Hertz is for periodic phenomena; becquerel is for radioactive decay. The SI brochure discourages the use of counting units such as &#x27;request&#x27;. The number of requests is regarded as just a number, or at best a quantity that is referred to the unit one. The applicable SI unit therefore is just the reciprocal second, s^(-1).<p>In practice, counting units are used everywhere (e.g., in MB&#x2F;s, the byte is a counting unit), but I am relaying what the SI brochure actually says on this question.<p>Ref: <a href="https:&#x2F;&#x2F;www.bipm.org&#x2F;en&#x2F;publications&#x2F;si-brochure&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.bipm.org&#x2F;en&#x2F;publications&#x2F;si-brochure&#x2F;</a>
评论 #39242177 未加载
评论 #39242110 未加载
评论 #39243003 未加载
评论 #39252012 未加载
评论 #39246061 未加载
评论 #39242325 未加载
rollcat超过 1 年前
I propose that we shall use bananas as the unit for request rate (one banana = one request per second); it&#x27;s obviously appropriate as:<p>1. Bananas are the de-facto standard for measuring the relative size of things posted online. Request rate is a relative quantity, since requests can have varying payload sizes, transfer rates, or server-side resource usage, even within the context of a single service (unlike decay rate, which to my understanding is usually considered within the context of a uniform sample of radioactive material).<p>2. The web has been steadily turning more toxic over the past several decades; you could call it a form of decay, but all radioactive decay eventually produces stable elements; no such trend has been observed with the web.<p>3. While bananas can trip up radiation detectors, they are much more likely to just go bad - same with web requests on your server; if you can&#x27;t process them in a timely manner, better just throw them away.
评论 #39242963 未加载
评论 #39244045 未加载
GlenTheMachine超过 1 年前
As a controls engineer, I strongly discourage using hertz as a measure of events. It&#x27;s an abuse of notation.<p>In control theory and signal processing, we refer to the frequencies that make up a signal in hertz. The maximum frequency a control law can track is called its bandwidth, which is in hertz. Frequencies a filter is passing or stopping are in hertz.<p>Computers being digital, we have to run that control law or signal processing algorithm at some rate. That rate also gets referred to in hertz, a lot, and it is a cause of no end of confusion, because the running rate of the algorithm is very much <i>not</i> the same as the bandwidth or filter bandpass. The Nyquist criterion says that the algorithm has to run at least twice as fast as the frequency of interest, but practice more like ten times faster. SO when we refer to a control law as &quot;500 Hz&quot; or whatever, I have to explain which sense I mean <i>every damn time</i>.<p>Don&#x27;t do it. Events happen at events per second. Hertz refers to sine waves, and NOTHING ELSE.
评论 #39246972 未加载
jonathrg超过 1 年前
There is a standard for these kinds of things, the IEC-80000 part 13 defines quantities related to information science and technology. The one that is closest to request rate is probably &quot;call intensity &#x2F; calling rate&quot;.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;ISO&#x2F;IEC_80000#Part_13:_Information_science_and_technology" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;ISO&#x2F;IEC_80000#Part_13:_Informa...</a><p>This standard doesn&#x27;t get much use. Mateusz Pusz, author of the C++ library mp-units, recently discovered it and has incorporated it into v2. <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=l0rXdJfXLZc" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=l0rXdJfXLZc</a>
AnotherGoodName超过 1 年前
Well si doesn&#x27;t really care about distributions. So it&#x27;s a gamma distribution with an average rate in hz. Don&#x27;t bother looking for the distribution in the units.
prpl超过 1 年前
Counts per second doesn’t need a unit. It’s probably closer to flux (generic definition, not specific definition).<p>counts per second is common in particle physics
评论 #39242500 未加载
zokier超过 1 年前
Wikipedia has short section for this<p>&gt; Aperiodic frequency is the rate of incidence or occurrence of non-cyclic phenomena, including random processes such as radioactive decay. It is expressed with the unit of reciprocal second (s⁻¹)[14] or, in the case of radioactivity, becquerels.[15]<p>&gt; It is defined as a rate, f = N&#x2F;Δt, involving the number of entities counted or the number of events happened (N) during a given time duration (Δt);[citation needed] it is a physical quantity of type temporal rate.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Frequency#Aperiodic_frequency" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Frequency#Aperiodic_frequency</a>
jedberg超过 1 年前
We already have a unit: RPS. Requests per second.
diarrhea超过 1 年前
I don’t understand what’s wrong with Hz. Bq is almost viciously misguided.
评论 #39241973 未加载
评论 #39242729 未加载
smcameron超过 1 年前
I thought qps (queries per second) was bog standard.
bvrmn超过 1 年前
&gt; Saying “ninety kilobecquerel” and writing “90 kBq” is a lot more convenient than “ninety thousand requests per second” and “90,000 requests&#x2F;s”.<p>I think current norm is 90k rps (or qps, but it&#x27;s clear in both cases).
nyrikki超过 1 年前
Easier solution which increases your chance of being compatible with the rest of the world:<p>Just use the ECMAScript Language Specification&#x27;s Time-related Constants algorithms like SecFromTime (t)<p><a href="https:&#x2F;&#x2F;tc39.es&#x2F;ecma262&#x2F;#sec-time-related-constants" rel="nofollow">https:&#x2F;&#x2F;tc39.es&#x2F;ecma262&#x2F;#sec-time-related-constants</a><p>Even the draft of w3c&#x27;s High Resolution Time just incorporate them.<p><a href="https:&#x2F;&#x2F;www.w3.org&#x2F;TR" rel="nofollow">https:&#x2F;&#x2F;www.w3.org&#x2F;TR</a><p>The ECMAScript Language Specification algorithms will help with rounding<p>SI allows for Quotients of SI units using either a solidus (&#x2F;) or a negative exponent.<p>Herz is just the reciprocal of the second, 1&#x2F;s or s^-1<p>Just as meters per second == m&#x2F;s == m*s^−1<p>1 Hz == ∆_Cs&#x2F;9,192,631,770 1 Sec == 9,192,631,770&#x2F;∆_Cs<p>As Hertz is just a special name for s^-1 or 1&#x2F;s, one can simply use the common prefixes and be mostly in sync with common standards from place like the w3c or their incorporated sources is far better than using SI for SI&#x27;s sake.<p>Most languages have those typedefs for their duration classes&#x2F;methods&#x2F;functions anyway. But the ECMAScript spec above allows you to implement one that will be inter-compatible without trying to invent new or use obscure units.
thadt超过 1 年前
&gt; It should be emphasized that activity measures the source disintegration rate, which is not synonymous with the emission rate of radiation produced in it&#x27;s decay. Frequently, a given radiation will be emitted in only a fraction of all the decays, so a knowledge of the decay scheme of the particular isotope is necessary to infer a radiation emission rate from its activity.[1]<p>It&#x27;s a metric for a source - not a receiver. So if we&#x27;re going to use Becquerels, then we&#x27;re really talking about needing to characterize the sources making the requests, not the servers receiving them. Which is great information to characterize, but still leaves us needing a metric for counting the requests seen vs those that are started but never reach the server.<p>If we&#x27;re still excited about doing things like people measuring radiation, then we could use counts per time unit. Like, counts per second, for example.<p>BUT - not all requests are equal. Next up, we measure how many resources are consumed in serving each request. I expect my next system dashboard to have a metric for RES (Röntgen Equivalent Server).<p>[1] Knoll, &#x27;Radiation Detection and Measurement&#x27; (3rd Ed) p2.
rerdavies超过 1 年前
Hopefully, anyone who is using becquerels for request rates is also using the delightfully obscure SI unit, the erlang.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Erlang_(unit)" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Erlang_(unit)</a><p>The unit symbol for Erlang is E.<p>The Erlang unit is used in telecommunications, where it is used in calculations that involve queueing problems. In telecommunications, it can be used to measure the load placed on a communications channel by an average request.<p>This leads to the delightful identity (for those who were asking for identities):<p><pre><code> E = Bq&#x2F;Bq[Max] </code></pre> Where Bq[Max] is the the maximum possible number of requests that can be serviced in one second of CPU time if those request were serviced sequentially.
评论 #39248903 未加载
mci超过 1 年前
How about a third unit, baud [1]? It looks no worse than hertz to me:<p>In telecommunication and electronics, baud (&#x2F;bɔːd&#x2F;; symbol: Bd) is a common unit of measurement of symbol rate, which is one of the components that determine the speed of communication over a data channel. It is the unit for symbol rate or modulation rate in symbols per second or pulses per second.<p>[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Baud" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Baud</a>
评论 #39242804 未加载
tussa超过 1 年前
Just because something can be counted in a fixed timeframe doesn&#x27;t mean it makes sense to slap a Hz unit on it.<p>What&#x27;s your frequency (in Hz) of sexual intimacy?
PeterStuer超过 1 年前
We alteady have time as measured in seconds. &quot;Requests&quot; are at best an ill defined concept measured as a discrete quantify. I see no reason to &#x27;standardize&#x27; beyond requests per second in a given context imho.
IshKebab超过 1 年前
This is stupid. The unit is &quot;requests&#x2F;s&quot;.
评论 #39242915 未加载
bjourne超过 1 年前
When you say that someone is 1.90 m tall what you&#x27;re <i>actually</i> saying is that their height is given by a random variable whose expected value is 1.90 m. Usually that random variable is a Gaussian with a very small standard deviation. In case of human height perhaps 0.005 m since height varies slightly during the day and measurements are inexact. Saying the request rate is 4 Hz works the same, except here the random variable (probably) is Poisson distributed with expected value 4.
charles_f超过 1 年前
I only count my requests in pints per fortnight.
评论 #39246453 未加载
leeoniya超过 1 年前
mechanical watches use a weird vibrations per hour. so instead of 4hz you get an unintuitive but impressive 28,800vph<p><a href="https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Vibrations_per_hour" rel="nofollow">https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Vibrations_per_hour</a>
kragen超过 1 年前
for some reason i got a lot of pushback when i tried to implement this terminology at a previous job
评论 #39246437 未加载
paulsutter超过 1 年前
If becquerel why not microfortnight? (about a second)
评论 #39248852 未加载
评论 #39241676 未加载
评论 #39241688 未加载