From: Martin Kronbichler Date: Mon, 14 Aug 2023 15:30:20 +0000 (+0200) Subject: Add changelog X-Git-Tag: relicensing~592^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6d92ba34b7432b8df938f48d69d0fd60d9c35061;p=dealii.git Add changelog --- diff --git a/doc/news/changes/minor/20230814Kronbichler b/doc/news/changes/minor/20230814Kronbichler new file mode 100644 index 0000000000..e1499eff0a --- /dev/null +++ b/doc/news/changes/minor/20230814Kronbichler @@ -0,0 +1,12 @@ +Improved: deal.II now has a flag DEAL_II_USE_VECTORIZATION_GATHER to control +the use of gather/scatter instructions on the x86 architecture. On a wide +range of Intel hardware with microcode mitigation for the Intel Gather Data +Speculation (GDS, aka Downfall) side channel vulnerability, in particular, +server processors of the Broadwell, Skylake, Cascade Lake, and Ice Lake +families released between 2015 and 2021, these instructions can be much slower +than scalar loads. While the default behavior of deal.II is to aggressively +enable these instructions in the intrinsics-class VectorizedArray, the new +variable can be used to disable their use if deemed to give better +performance. +
+(Martin Kronbichler, Matthias Maier, 2023/08/14)