Monday Feb 09, 2015

VirtualBox: expose SIMD instructions

I'm copying info which circulated internally.

Certain versions of VirtualBox software, for unknown reason, hide SIMD instructions from guest VMs.
This affects DB12c Database In-Memory performance.

You can check whether Vbox hide "SSE4.2" instruction by looking inside log just when
guest is starting up.

$ grep -E 'Mnemonic|SSE4.2' VirtualBox\ VMs/IM/Logs/VBox.log
00:00:00.776827 Mnemonic - Description                 = guest (host)
00:00:00.776890 SSE4.2 instruction extensions          = 0 (1)

'0' means 'hidden'.

You can also check inside guest OS. If guest OS is Linux,

$ sudo grep sse4 /proc/cpuinfo
flags           : fpu [...] ssse3 sse4_2 lahf_lm

The result above includes "sse4_2" but your result doesn't probably contain it.

The workaround is to run the command below in host OS.

$ VBoxManage setextradata "VM name" VBoxInternal/CPUM/SSE4.2 1

So, please try this especially when you try Database In-Memory in VirtualBox.

Thursday Feb 05, 2015

SQL Developerの新しいDBA画面

以下のような画面がリリース予定です。JavaFXで実装されたUIです。実際にExadataに接続しキャプチャーしてみました。右側が見切れてしまうと思いますが右クリックなどで画像のみ表示すれば全体を見れます。

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The views expressed on this blog are my own and do not necessarily reflect the views of Oracle.

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