eden + survivors must be small (!too small)

I used to wonder why young generation (eden+survivors) should not be larger than ¼ (or 1/8….can’t remember the recommendation). The reason turns out to be fundamental and it’s good to remember it.

Reason is, minor GC is very frequent and is expected to be efficient and “cheap”. Long pause is associated with major GC, whereas minor GC STW pause is usually much shorter.

Note Even though minor GC is brief, it is Stop-The-World throughout. There are no phases. There’s just one phase and it’s STW.

Many financial trading engines incur just one major GC a day, but no such thing about minor GC.

General advice/observations —

* young gen too large -> bad pause during minor GC
* young gen too small -> too frequent minor GC

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s