Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date: Sun, 3 Feb 2013 12:40:07 +0100
From: magnum <>
Subject: Re: Avoiding AMD ASIC hangs

On 3 Feb, 2013, at 7:57 , Solar Designer <> wrote:
> On Sat, Feb 02, 2013 at 10:49:38PM -0800, Brian Wallace wrote:
>> Solar requested that I implement a split kernel to pwsafe-opencl to avoid
>> AMD ASIC hangs.  Specifically, it was requested I ask magnum about the
>> right way to go about this.  I won't be able to implement this right away,
>> but I should be able to in the coming week.  How should I go about this?
> As I wrote in the original thread on pwsafe, before I saw your posting above:
> Brian - basically, individual kernel invocations should be taking no
> more than 200ms, preferably much less.  This means that with a large
> GWS, you need to be computing only a fraction of the 2048 iterations per
> kernel invocation.  Please store intermediate results in global memory.
> Some examples:
> fgrep HASH_LOOPS opencl_*.c opencl/*

The key to success is to not transfer anything to/from kernel between loop invocations but store the data needed in global memory. Then pick a HASH_LOOPS that takes about 10-20 ms per call for the loop kernel.

For processing events within the loop, see


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.