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A lot of complex “scalable” systems can be done with a simple, single C++ server

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Re: A lot of complex “scalable” systems can be done with a simple, single C++ server

#221

Post by Const-me »

pkolaczk wrote: post #194
Const-me wrote: post #140

Earlier quoted context omitted.

This. Modern C# in net-core 3 can even match C++ at manually vectorized numeric code: https://github.com/dotnet/coreclr/issues/27909#issuecomment-...

While I agree they can sometimes compete in numerically heavy tasks, the place where they fall behind is memory management. Systems like databases need very careful memory management and GC is not always your friend there. I'm still hoping some day we'll be allowed both GC and Rust-like manual memory management in a single language, although I'm not sure it is at all possible.

> the place where they fall behind is memory management

It's sometimes possible to design C# code in a way that doesn't stress GC too much, so the majority of bandwidth bypasses the GC.

For instance, here's my old .NET project which plays streaming media for hours without interrupts, with a hard limit of 15MB RAM for the whole process: https://github.com/Const-me/SkyFM

Doing so became easier in modern .NET, with these value tuples and spans.

> still hoping some day we'll be allowed both GC and Rust-like manual memory management in a single language

Microsoft tried, managed C++, then C++/CLI. The CLI is still supported if you want to try, but IMO they both were way too complex: 2 types of pointers, two runtimes with weird interaction between them, worst of both sides on safely and ease of use.

AFAIK most people only used these languages for a thin layer of glue to integrate native C++ with C#. And even for that limited use case, COM interop or C interop often worked better. Even MS switched to COM interop in the next iteration, C++/CX.

Re: A lot of complex “scalable” systems can be done with a simple, single C++ server

#222

Post by masklinn »

jcelerier wrote: post #198
usrnm wrote: post #166

Earlier quoted context omitted.

On the other hand, not using atomics in heavy multithreaded code is just a recipe for disaster. The problem with shared_ptr is the fact that it uses atomics even in single-threaded code, which is obviously an overkill.

> The problem with shared_ptr is the fact that it uses atomics even in single-threaded code, which is obviously an overkill. On the other hand imagine the security issues if shared_ptr was not thread-safe - you could just not reliably destroy a shared_ptr in any thread. If you really know that you're going to get a graph of shared_ptr that do not move of a single thread, you can use boost::local_shared_ptr explicitel…

One of the advantages of rust is its ability to segregate safe-to-share (between concurrent contexts) and not so, at compile time.

While it can’t (yet?) be generic over them, it lets you use the non-atomic Rc in thread-bound structures and know this is never going to be shared between threads, whereas the more expensive Arc can have handles be moved from one thread to an other.

Re: A lot of complex “scalable” systems can be done with a simple, single C++ server

#223

Post by inetknght »

hnews_account_1 wrote: post #132
jandrewrogers wrote: post #47

Many developers severely underestimate how much workload can be served by a single modern server and high-quality C++ systems code. I've scaled distributed workloads 10x by moving them to a single server and a different software architecture more suited for scale-up, dramatically reducing system complexity as a bonus. The number of compute workloads I see that actually need scale-out is vanishingly small even in indu…

Can you expand on this? I have some pretty massive compute loads that need to be scaled onto a cluster with 100+ workers for most computations. This is after I use a library called dask that graphically does its own mapreduce optimisation inside its modules. This is all for a relatively small 250GB raw data file that I keep in a csv (and need to convert to SQL at some point). Are you saying this can be optimised to f…

> Are you saying this can be optimised to fit inside a single 10 core server in terms of compute loads?

I'm currently employed to write software which does DNA analysis. DNA is known for being Big Data.

Some applications are very compute intensive and others are very data-relation intensive. The very compute intensive applications process about 1GB of data in about 30 minutes on a 32 core Xeon 6xxx with 32GB of RAM assigned to it. The data-relation intensive application processes about 350GB of data in 15 minutes on a single core of the same CPU but with 700GB of RAM assigned to it.

Both are heavily optimized but in different ways. So without knowing more about what you're doing with that data, it's hard to say.

Re: A lot of complex “scalable” systems can be done with a simple, single C++ server

#224

Post by giantrobot »

hnews_account_1 wrote: post #132
jandrewrogers wrote: post #47

Many developers severely underestimate how much workload can be served by a single modern server and high-quality C++ systems code. I've scaled distributed workloads 10x by moving them to a single server and a different software architecture more suited for scale-up, dramatically reducing system complexity as a bonus. The number of compute workloads I see that actually need scale-out is vanishingly small even in indu…

Can you expand on this? I have some pretty massive compute loads that need to be scaled onto a cluster with 100+ workers for most computations. This is after I use a library called dask that graphically does its own mapreduce optimisation inside its modules. This is all for a relatively small 250GB raw data file that I keep in a csv (and need to convert to SQL at some point). Are you saying this can be optimised to f…

You have 250GB of "raw" data stored in CSV format. The parsed version of this data in memory is likely to be a fraction of the on-disk size. A `long` or `double` only take up eight bytes in memory but 10-20 bytes on disk stored as ASCII in a CSV file. Even if your raw data was 250GB you could store it in memory mapped files. A fast SSD can easily hit a gigabyte per second sequential read speed, far faster than your typical network.

Segmenting your raw data and using memory mapped files will let you work with large data sets without needing huge amounts of RAM. From there it's a question of your single system's processing speed and IO capacity. This is only necessary if your processing needs random access to the entire dataset.

If your CSV data is more like a streaming data source, you're processing each record as it's read in, you can just stream it in through `stdin`. At 1GB/s you're looking at five minutes or so to process your 250GB of raw data. A SATA SSD might take twenty minutes to stream that raw data.

Re: A lot of complex “scalable” systems can be done with a simple, single C++ server

#225

Post by cthalupa »

bsenftner wrote: post #56

I'm 15 years in writing high performance Internet servers in C++, and I can confirm higher level languages provide an illusion of capability, but once you're talking high performance with high compute requirements and scaling your service, the cost efficiency of C++ is exponential better than any other language. The higher level language ecosystems are bloated beyond repair. I was able to use one 32-core physical ser…

The thing that worries me about stories like this is that there is frequently (as is the case here) no mention any sort of HA or backups. No details on what disaster recovery looks like. Those are business critical considerations that cost money, and just disappear from the discussion when people say "hey i saved all this money dropping everything down to a single server!"

Re: A lot of complex “scalable” systems can be done with a simple, single C++ server

#226

Post by Narishma »

bagels wrote: post #199
hnews_account_1 wrote: post #132

Earlier quoted context omitted.

Can you expand on this? I have some pretty massive compute loads that need to be scaled onto a cluster with 100+ workers for most computations. This is after I use a library called dask that graphically does its own mapreduce optimisation inside its modules. This is all for a relatively small 250GB raw data file that I keep in a csv (and need to convert to SQL at some point). Are you saying this can be optimised to f…

Not who you asked, but, it's hard to say without knowing exactly what computation is being done, or how much of the time is spent on IO. If you organize that 250GB in ram the right way (cache coherency, right container types), and spend a lot of effort doing analysis of algorithm selection, you might be surprised how much you can get done on a single (large) machine with enough cores.

Cache locality, not coherency.

I'm curious as to why this seems like a common mistake (I've seen it a few times already in this comment section).

Re: A lot of complex “scalable” systems can be done with a simple, single C++ server

#227

Post by IanCal »

pnako wrote: post #210
buzzkillington wrote: post #171

Earlier quoted context omitted.

I've worked at BigCo. It's resume padding with the fear of looking like an idiot for not knowing about the new tech. We were going to go all in on Snowflake with everyone on the team being for it. I sat down, read the original whitepaper, wrote a simulation of what the costs would look like with the current read/write statistics and tested a small batch of data on it to double check. Turns out we would have paid betw…

I'm starting to wonder if there is market to do "technology laundering", use things like PostgreSQL, SQLite, standard Unix tools, put it under some cloud marketing and charge a x10 premium. Or perhaps not only there is market, but that's more or less what everyone is already doing.

If you can set it up so it solves my problems, yes.

I could manage my own server and fine tune everything, or I can throw it on snowflake. Snowflake means I've spent almost no time managing anything and it was costing less than an aws box running postgres but absolutely blew it out of the water performance wise. Depends on your workload but it's been perfect for one of my use cases. If they were just using postgres under the hood and I got the same en experience - fine.

Big things are time sharing resources and management/updates/etc. Can you charge me 10x the underlying cost but let me pay for two minutes on a wildly powerful machine? Great, that's a net win for me.

Re: A lot of complex “scalable” systems can be done with a simple, single C++ server

#228

Post by Too »

ospider wrote: post #214
lmm wrote: post #109

Earlier quoted context omitted.

The idea that GCed languages in general have Python-like performance is a dangerous myth. Languages that are managed but not interpreted (e.g. Java, OCaml, Haskell, C#, Swift) have performance characteristics that are much closer to C than to Python.

Actually, Python is compiled to its bytecode and then interpreted by the Python VM, which is also how Java works. Python is slow because the lack of funds and people's focus, just take look at how fast JavaScript(V8) is nowadays.

No, Python bytecode is still interpreted at runtime. Java, JS and .NET is first compiled into bytecode but then they are also JIT-compiled into machine code which Python is not.

You can JIT Python also using https://www.pypy.org/ but it's not the default and it's not 100% official and compatible.

Re: A lot of complex “scalable” systems can be done with a simple, single C++ server

#229

Post by [deleted] »

jhgg wrote: post #186
IndrekR wrote: post #54

A site for proof. It keeps amusing me on what hardware/software Stack Overflow/Stack Exchange is running on: https://stackexchange.com/performance This is way less in HW than most people in the trade (from web devs to devops) seem to think when asked about it. SO ranks #36 in Alexa right now: https://www.alexa.com/siteinfo/stackoverflow.com

SO is really not a great example of a high traffic site. 5500 req/sec of mostly read only traffic is not that crazy at all, and their hardware footprint is incredibly over-provisioned for the workload. I don't really think their example stands well here. For example, at work, our entire analytics ingest workload (HTTP) for a few hundred million users runs on 8 core VMs on GCP, written in Rust/Go, each node doing ~40k…

[deleted]

Re: A lot of complex “scalable” systems can be done with a simple, single C++ server

#230

Post by z0mbie42 »

jhgg wrote: post #186
IndrekR wrote: post #54

A site for proof. It keeps amusing me on what hardware/software Stack Overflow/Stack Exchange is running on: https://stackexchange.com/performance This is way less in HW than most people in the trade (from web devs to devops) seem to think when asked about it. SO ranks #36 in Alexa right now: https://www.alexa.com/siteinfo/stackoverflow.com

SO is really not a great example of a high traffic site. 5500 req/sec of mostly read only traffic is not that crazy at all, and their hardware footprint is incredibly over-provisioned for the workload. I don't really think their example stands well here. For example, at work, our entire analytics ingest workload (HTTP) for a few hundred million users runs on 8 core VMs on GCP, written in Rust/Go, each node doing ~40k…

Hi, I'm curious because I plan to rewrite a Rust service to Go (development velocity is too slow) Which part of your service is in Rust amd which in Go? Do you think that if it would be only in Go it could sustain such a load?
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