Can a Changeling with the actor feat have permanent advantage and performance and Deception checks?

So the changeling’s shapeshift ability says that

As an action, you can change your appearance and your voice. You determine the specifics of the changes, including your coloration, hair length, sex, height and weight. You can make yourself appear as a member of another race, though none of your game statistics change. You can’t duplicate the appearance of a creature you’ve never seen, and you must adopt a form that has the same basic arrangement of limbs that you have. Your clothing and equipment aren’t changed by this trait.

So basically, as long as the person you are changing into is/ was a real person, you are always passing yourself off as a different person.

The Actor feat says

You gain +1 CHA, you have advantage on Deception and Performance checks when trying to pass yourself off as a different person, and you can mimic the speech of another person or the sounds made by other creatures that you have heard (for at least 1 minute).

So the way I read it, a changeling would always have advantage on Deception and Performance checks because they are always trying to pass themselves as a different person. Or is the meaning of the Actor feat that they only have advantage when they are trying to prove that they are a different person not in other situations? Really curious if this is kinda broken because a bard or rogue with expertise and advantage on all deception checks could be a crazy good liar.

Why do powerful programming languages have lower performance?

I was reading this article. The author talks about "The Blub Paradox". He says programming languages vary in power. That makes sense to me. For example, Python is more powerful than C/C++. But it’s performance is not as good as C/C++.

Is it always true that more powerful languages must necessarily have lesser performance when compared to their less powerful counterparts? Is there a law/theory for this?

MySQL InnoDB Weird Query Performance

I designed two tables, both using InnoDB. The first one has columns “Offset, Size, and ColumnToBeIndexed” with BIGINT “Offset” being the primary key, and the second one has columns “OffsetAndSize, and ColumnToBeIndexed” with BIGINT “OffsetAndSize” being the primary key. And there are both 15 millions rows in each table. I added indexes to both tables on “ColumnToBeIndexed.”My two queries for them are “SELECT Offset, Size FROM someTable WHERE ColumnToBeIndex BETWEEN 20 AND 10000 ORDER BY Offset ASC” and “SELECT OffsetAndSize FROM someTable WHERE ColumnToBeIndex BETWEEN 20 AND 10000 ORDER BY OffsetAndSize ASC.” Because the second query could use the secondary index and does not need to look up the clustered index to find the “size” information, I expected that the second query on the second table performs better than the first query on the first table. However, as the test came out, it turned out that the first query performs better every single time. Does anybody out there know what seems to be the problem?

Help with performance and speed-up question related to number of cores and their areas

There is a question in my exam that said:

Consider the following three processors (x, y, and z) that are all of varying areas. Assume that the single-thread performance of a core increases with the square root of its area.

  1. Processor X, core area = A

  2. Processor Y, core area = 4A

  3. Processor Z, core area = 16A

You are given a workload where S fraction of its work is serial and 1 – S of its work is infinitely parallelizable.

a. If executed on a die composed of 16 Processor X’s, what value of S would give a speedup of 4 over the performance of the workload on just Processor X?

b. Given a homogenous die of area 16A, which of the three processors would you use on your die to achieve maximal speedup? What is the speedup over just a single Processor X? Assume the same work load as in part b.

My progress with this part so far:

In an area of 16A, 4 cores of Y would fit. The square root of its area is $ 2\sqrt{A}$ , which each of the four cores’ performance would increase by a factor of two? Using Amdahl’s law,

Overall speed-up for this choice $ =\dfrac{1}{\dfrac{1 – S}{4(2)?} + S}$

And likewise, the overall speed-up for choosing 1 core of Z $ =\dfrac{1}{\dfrac{1 – S}{1(4)?} + S}$

I am assuming that 1 core of area 4A is like 2 cores of area A, is this a valid assumption? For S = 0.2, 4 cores of Y would yield a higher speedup than one core of Z. Is this reasoning correct?

How to improve wordpress mysql performance on large tables?

I’ve installed WordPress 5.4.1 on Ubuntu 20.04 LTS on AWS EC2 (free tier as I’m starting).

My instance has 30 GB of disk space and 1 GB of RAM.

My website has at about 9000 pages and I’ve imported 7800 so far with “HTML Import 2” plugin.

wp_posts table has 7,800 rows and 66 MB size and, since this table has grown, wordpress has become super slow. Any change I make to the database is super slow as well.

While trying to make changes, I keep getting this error:

Warning: mysqli_real_connect(): (HY000/2002): No such file or directory in /var/www/wordpress/wp-includes/wp-db.php on line 1626 No such file or directory

Error reconnecting to the database This means that we lost contact with the database server at localhost. This could mean your host’s database server is down.

What could I do in order to achieve a better speed and make it usable?

How to troubleshoot SER performance

Looking for advice on how to troubleshoot SER performance / LpM. We went from about 150 LpM to about 20 LpM and can’t figure out what has changed. 

There are 12 projects but only 2-3 active. I have around 4,500,000 urls in my identified site list. Proxies seem pretty solid and haven’t changed (I’ve also tried without for short bursts to just check). Internet connection is 100 megabits and I’ve played around with my DNS service just to be sure I’m not rate limited. Use x-evil on two other LAN pcs for captchas. PC is core i7 + 8gb ram.  

When I start SER it just moves slow. CPU is at 1-5%. Can’t figure out what bottleneck to look for!

Does someone realize they were charmed after the effect of the Glamour bard’s Enthralling Performance wears off?

I have been playing a College of Glamour bard in the Tomb of Annihilation module. They get the Enthralling Performance feature at 3rd level when they choose the subclass (Xanathar’s Guide to Everything, p. 14):

If you perform for at least 1 minute, you can attempt to inspire wonder in your audience by singing, reciting a poem, or dancing. At the end of the performance, choose a number of humanoids within 60 feet of you who watched and listened to all of it, up to a number equal to your Charisma modifier (minimum of one). Each target must succeed on a Wisdom saving throw against your spell save DC or be charmed by you. […] This effect ends on a target after 1 hour, if it takes any damage, if you attack it, or if it witnesses you attacking or damaging any of its allies.

If a target succeeds on its saving throw, the target has no hint that you tried to charm it.

According to the description, the target does not become aware of the fact that someone attempted to charm them if they succeed at their saving throw. However, it doesn’t say anything about what happens if they fail their save and the charm wears off.

Once the effect of Enthralling Performance wears off, do those that were previously affected by it know they were charmed?

RPI cluster performance related to network performance

I’m writing my thesis and i have built a RPI cluster, containing 10 nodes which consists of RPI model 3b. I’ve them connected to two gigabit switches. I don’t know the CAT of the cables. They are not connected to the Internet, they just live in their private network.

Further more, i’ve calculated the theoretical performance by the formula:

number of cores * average frequency * 16 FLOPs/cycle = x GFLOPS (Got the formula from )

after i applied it, it turns out i should have 76,8 GFLOPS in theory assuming that the source is relaiable and correct. When i benchmark it using HPL 2.1 i’ve only reached little about 7 GFLOPS at best when trying out various variations.

Now to my question: i’ve read up on the RPI model, and it says it only have 10/100 Ethernet. Is that the source of my problem? Seeing i get out GFLOPS from a node, but the network transportation is much less then Gigabit speed which would mean 76,8 GFLOPS * 0,1 Gigabit/second = 7,68 GFLOPS (in theory). Or am i way off the tracks in my thinking?

I really appriciate any help, so i can know if i have to keep working on the configuration for the benchmarking or if i can move on. Also, i’m sorry if i have posted in the wrong place.

Stay safe out there!