Date: Wed, 25 Apr 2012 03:12:35 +0400 From: Solar Designer <solar@...nwall.com> To: john-dev@...ts.openwall.com Subject: GPU eager execution (was: New patch for OpenCL SHA-512) On Thu, Mar 22, 2012 at 08:00:54AM +0100, magnum wrote: > I believe both AMD's and Nvidia's compilers generate code for eager > execution in many cases (that is, unless the conditional blocks are too > large or too complex). I don't know much details but I suppose the real > problems begin when they do not: Normally all threads in a workgroup > execute in sync. FWIW, this presentation on GCN: http://developer.amd.com/afds/assets/presentations/2620_final.pdf gives some generated code samples that show that there's some hardware support for eager execution - "exec mask" (tells which of the work-items execute for real?) and the s_cbranch_vccz and s_cbranch_execz instructions (branch for real if the "exec mask" would remain full or if it became zero, respectively?) Alexander
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.