Linux Database Server CPU Comparison
by Johan De Gelas on June 17, 2005 12:05 AM EST- Posted in
- IT Computing
Benchmarks MySQL 4.0.18: Intel versus AMD
It must be said that the MySQL results had a large margin of error (3% - 4%) compared to DB2, especially at high levels of concurrency.
Here is our MySQL configuration:
Read_buffer=2GB
Port=3306
socket = /var/lib/mysql/mysql.sock
skip-locking
set-variable = max_user_connections= 2000
set-variable = max_connections= 2000
key_buffer=2G
Read_buffer=2G
table_cache=1024
tmp_table=128M
max_heap_table=256M
read_rnd_buffer = 64M
thread_cache=16
net_buffer_length=16k
The " query cache" was off, as we wanted to test worst case performance. In some cases, the query cache was able to push a single Xeon to 1000 queries per second, and the CPU was still capable of doing more, as the CPU load was at 50% - 70%. At 1000 queries/s and more, other bottlenecks started to kick in, such as the latency of the network driver, the operating system and so on.
All numbers are expressed in queries per second. All concurrency tests below 5 are not reliable enough to make any firm conclusion as the margin of error is much higher.
| Concurrency | Dual Xeon (Gallatin) with L3 cache |
Single Xeon (Gallatin) with L3 cache |
Dual Xeon (Nocona) with HT |
Single Xeon (Nocona) with HT |
Dual Xeon (Irwindale) 3.6GHz with HT |
Dual Core Intel 3.2GHz |
Dual Opteron 250 2.4Ghz |
Single Opteron 250 2.4GHz |
Single Opteron 252 2.6 GHz |
| 1 | 243 | 248 | 280 | 277 | 286 | 233 | 290 | 298 | 319 |
| 2 | 357 | 317 | 423 | 338 | 450 | 344 | 438 | 370 | 399 |
| 5 | 466 | 356 | 473 | 358 | 497 | 442 | 543 | 435 | 470 |
| 10 | 505 | 361 | 521 | 375 | 517 | 487 | 629 | 465 | 502 |
| 20 | 496 | 350 | 531 | 371 | 545 | 507 | 670 | 455 | 498 |
| 35 | 508 | 355 | 555 | 371 | 506 | 490 | 665 | 470 | 507 |
| 50 | 497 | 348 | 526 | 368 | 495 | 502 | 669 | 472 | 508 |
| AVG | 494 | 354 | 521 | 368 | 512 | 486 | 635 | 460 | 497 |
| MAX | 508 | 361 | 555 | 375 | 545 | 507 | 670 | 472 | 508 |
Those were the raw numbers. Let us now analyse this...
| Concurrency | Dual versus Single Xeon Galatin | Dual versus Single Xeon Nocona/ Irwindale | Dual Opteron 250 vs Single |
| 1 | -2% | 1% | -3% |
| 2 | 12% | 25% | 18% |
| 5 | 31% | 32% | 25% |
| 10 | 40% | 39% | 35% |
| 20 | 42% | 43% | 47% |
| 35 | 43% | 50% | 41% |
| 50 | 43% | 43% | 42% |
| AVG | 40% | 41% | 38% |
MySQL ISAM is an incredibly fast database engine in our benchmark situation: it handles the same workload about twice as fast as DB2. I have to emphasize "our benchmark situation" because we cannot forget that our workload is mainly about reading the database and not writing. And of course, it must be said that the MySQL ISAM engine does less work on each query than DB2; it does not support transaction-safe (ACID compliant) commit, rollback, and crash recovery capabilities.
MySQL, as we have also noticed 6 months ago, doesn't seem to scale as well as DB2. At best, you get a 40% - 45% performance increase when the concurrency level is high enough. When we move to quad CPUs, we only get a 20% - 30% increase while DB2 still offers a 70% increase. The better scaling of DB2 means that with enough CPUs, it runs almost as fast as the MySQL ISAM engine, and offers all the transaction-safe capabilities as a bonus.
Let us check if the architectural differences between the CPUs make a difference . Again, don't pay too much attention to the results of the lower concurrency levels.
| Concurrency | Dual Xeon Irwindale versus Nocona (3,6 GHz) | Xeon Nocona (3,6 GHz) vs Galatin (3,06) | Opteron 2.6 vs Nocona 3.6 | Opteron 2.6 vs Pentium-D | Xeon Nocona 3,6 GHz vs Pentium-D |
| 1 | 2% | 12% | 15% | 37% | 19% |
| 2 | 6% | 7% | 18% | 16% | -2% |
| 5 | 5% | 1% | 31% | 6% | -19% |
| 10 | -1% | 4% | 34% | 3% | -23% |
| 20 | 3% | 6% | 34% | -2% | -27% |
| 35 | -9% | 5% | 37% | 4% | -24% |
| 50 | -6% | 6% | 38% | 1% | -27% |
| AVG | -2% | 4% | 35% | 2% | -24% |
| MAX | -2% | 4% | 36% | 0% | -26% |
The bigger L2-cache of the Xeon Irwindale did nothing more than compensate for the slightly higher latency of the L2-cache. The Xeon Irwindale and Nocona perform alike.
MySQL, unless you get the special Intel Compiler optimized version, remains the stronghold of the Opteron. The fastest (single core) Opteron outperforms the best Intel CPU by a 35% margin. We didn't use the Intel compiler version as we have reason to believe that this version is not used a lot in the real world. We might try it out in a future article.
The relatively limited scaling also means that high clocked single CPUs can be an interesting option. This is illustrated by the Opteron 252 2.6 GHz, which outperforms the dual core Pentium-D 3.2 GHz by a small margin.
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linuxnizer - Tuesday, July 19, 2005 - link
Late contribution...The article mentions that Linux didn't work well with AMD Dual Core. The reason could be this:
http://www.iwill.net/inews.asp?n_id=35
it says:
NVIDIA CK804 does not support dual core under Linux yet, only under Microsoft Windows.
Illissius - Saturday, June 18, 2005 - link
Nice article. I'd also be interested in PostgreSQL, being the "other" major open source database... specifically, whether it's any better at scaling with multiple CPUs. (Not that I have any practical use for this information, I'm just curious.)Viditor - Saturday, June 18, 2005 - link
Seriously, mickyb and elmo may be correct about the Intel compilers (I frankly don't have a clue what's used in most shops)...The real problem is that it's a virtual impossibilty to create a "level playing field", but I have to say to the critiques of the article that Johan has done a stellar job of coming as close as possible!
Viditor - Saturday, June 18, 2005 - link
"They aren't testing compilers"Oh sure...just throw REALITY into the mix why don't you...!
;-)
Icehawk - Saturday, June 18, 2005 - link
They aren't testing compilers.Viditor - Saturday, June 18, 2005 - link
mickyb - Thanks for the input! Fair enough...maybe Johan could use both the Pathscale compiler (which is optimized highly for Opteron) and the Intel optimized compiler on his next series of tests?mickyb - Saturday, June 18, 2005 - link
I dissagree with the comment that a large number of people don't use the Intel compiler. I (other developers and IT shops) only use Intel compiler's for Linux. It is the fastest one out there for x86 and Itanium.If you are running a large database that requires a large server (compared with a desktop loaded with RAM to run a personal blog site) like this article is testing, you will be setting up the environment with a trained IT professional that will use the compiler that is fast and stable.
When we build our product for all the UNIX platforms, we always use the vendor compiler instead of gnu. gnu works great and is free, but it is not optimized nearly as much.
This is like saying the same audience won't recompile Linux on the platform they are going to install it on. This is the first thing you should do....and with an Intel compiler. There should be no real reason why one vendor Linux is faster than the others except for compile options and loaded modules. You cannot run Linux out of the box, it doesn't come in a box where I get it. :)
DonPMitchell - Saturday, June 18, 2005 - link
We need to see TPC-C benchmark results for MySQL and other new database systems. Why won't they step up and allow themselves to be compared to the major commercial systems?Viditor - Saturday, June 18, 2005 - link
ElMoIsEviL - "as much as I am un-biased"C'mon mate...anybody who has read your posts knows you're heavily biased towards Intel, just as people who have read mine know that I am biased towards AMD. The important thing is to try and set aside the bias to look at things from both sides...I do try, but admittedly don't ALWAYS succeed. :-)
I imagine you probably posted before you read the explanation of what a query cache is...understandable.
As to not using an Intel specific compiler, I suppose that if it HAD been used I would be complaining as well. We have to rely on Johan and Anand (who frankly know a Hell of a lot more about this than either of us) to choose based on what the market actually uses...if you can site impartial industry sources that show otherwise, I'm sure we would all (especially the AT staff) would love to see them.
I do know that over the years, Johan and Anand have shown themselves to be quite unbiased in their articles (you should go read some of them on Aces as well)!
There are certainly things that I could pick apart as well..e.g. when he states
"In the second half of 2004, already one million EM64T Xeons were shipped"
Yes they were shipped, but that doesn't mean they were sold. The majority of those shipments were probably to OEMs for inventory buildup. Remember that Intel had a huge inventory write-off at the same time, and this was most likely a shift in inventory.
Regardless, none of this has to do with the validity of the article which is excellent and makes sense. If you think about it, it should have been expected...the only for AMD to have increased their marketshare in servers is by performance. They certainly don't have the budget or marketing clout that Intel has!
S390 guy - Saturday, June 18, 2005 - link
About ISAM and DB/2... ISAM (Indexed Sequential Access Method) is NOT a database! It has no referential integrity nor rollback/commit features (although those can be activated on mainframe). ISAM was popular on mainframe when there wasn't any database (or rather when database was a too massive application to run!) and even there they were superseeded by VSAM. They're not much different from DOS random access files (an index file pointing to the relative record number on the main file).And it's no suprise that DB/2 scales well: mainframes rarely feature a single CPU, at least as far as I know.... IBM have had some 20 years to practice on multi-cpu machines!