AMD Milan versus Milan-X for large MariaDB database

Started by Kovtalo, Jun 17, 2022, 04:04 AM

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KovtaloTopic starter

Hello,
I read up on Milan-X lineup with large L3 cache.

However, I can't seem to figure out what looks better for a large MariaDB database.
Database size is about 800 GB, with much more reads than writes and a large innodb buffer pool keeping the hot spots nearly all in memory.

In such case would you recommend AMD Milan or AMD Milan-X?

We are considering dual 75F3 versus dual 7573X.

Thank you.
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jina

Both are going to provide quite a lot of performance.

256mb vs 768mb of cache is a big difference. Any operation that acts upon data in cache will be dramatically faster, and 3x the cache will make that happen more often.

The downside is the base clock speed and max turbo speed is lower on the Milan-X part you linked, so the X will be a little bit slower for all operations that are a cache miss, while the extra cache will make it be a lot faster some of the time, due to greater number of cache hits.

At the same price I would go with the X as the extra cache is -probably- useful, and in some use cases, will provide a massive performance gain. Worst case it will be slightly slower if you're unlucky that your use case doesn't benefit at all from the added cache.
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Movut

Sql db's are famously bottlenecked by ram for reads (cache1 and indexes) and iops for writes. You can find stackoverflow posts from ~10+ years ago discussing this.

Between the two cpu's I would go with the one with bigger L3 cache. Usually with sql db's, if you have started worrying about cpu clock speed, you're already doing something wrong.
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johngf

Quote from: Kovtalo on Jun 17, 2022, 04:04 AMHello,
I read up on Milan-X lineup with large L3 cache.

However, I can't seem to figure out what looks better for a large MariaDB database.
Database size is about 800 GB, with much more reads than writes and a large innodb buffer pool keeping the hot spots nearly all in memory.

In such case would you recommend AMD Milan or AMD Milan-X?

We are considering dual 75F3 versus dual 7573X.

Thank you.
If we talk about the price, but the AMD Milan processor has new cores at the old price, this is one of its features. And so they differ only in price and frequency, they have the same cache, so you need to choose with the highest processor frequency.
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yoginetindia

AMD has released today a new family of EPIC 7003X web server processors, also known by the codename Milan-X. The novelties are improved versions of the Milan chips released a year ago: they are also built on Zen 3 cores, but at the same time they received much more cache memory due to the presence of additional 3D V-Cache memory crystals.
In total, four models were presented, which number from 16 to 64 Zen 3 cores. All new products consist of eight chaplets with cores, on top of each of which an additional memory crystal is installed. This provides 96 MB of third-level cache not a chaplet: 32 MB on a chip with cores and 64 MB of 3D V-Cache. As a result, each Milan-X processor offers 768 MB of third-level cache, even the junior 16-core PIC 7373X.

The two older novelties have a standard TDP level of 280 watts, and the two younger ones have 240 watts. At the same time, each Milan-X TDP indicator can be adjusted in the range from 225 to 280 watts. Also, from the common features of all new products, we note the presence of eight DDR4 memory channels, and 128 PCI Express 4.0 lines. Milan chips are made in the same SP3 socket as their predecessors.

AMD EPIC 7003X processors will go on sale today. As for the cost, the 16-core PIC 73 X is priced at $4185, the 24-core will have to pay $3700, the EPIC 7573X model with 32 cores will cost $5490, and finally, the flagship 64-core EPYC 7773X will cost $8800. For comparison, the flagship of the Milan series — EPYC 7763 — is estimated by the manufacturer at $7790.
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