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Date: Thu, 25 Jul 2013 02:54:20 +0200
From: Katja Malvoni <kmalvoni@...il.com>
To: john-dev@...ts.openwall.com
Subject: Re: Katja's weekly report #6

On Wed, Jul 24, 2013 at 7:18 PM, Katja Malvoni <kmalvoni@...il.com> wrote:

> On Wed, Jul 24, 2013 at 2:28 AM, Solar Designer <solar@...nwall.com>wrote:
>

>
>  Maybe you can test similar data transfers in a dummy application that
>> would do very little computation (so it'd spend most of its time on the
>> transfers back and forth), but would instead deliberately try to detect
>> cases of out-of-order arrival?
>>
>
> I started with this - created and tested only data transfers (hash, key,
> start and done) without computation and than introducing variable delays
> using timers. And in all runs I did, data transfers were correct. I was
> checking data in same way I'm reading result now, again relying on having
> data there before done flag is set.
> I'll check it one more time, it won't take much time.
>

I tried those data transfers and it's not completely reliable. I'm
transferring key and hash (as char array) to core in a loop iterating
through test vectors, than compute sum of all array members and copy key
and hash to key_out and hash_out. All data is stored in shared memory. If
there is no computation on Epiphany side than in some cases it happens that
transfers aren't executed completely and data from previous iteration is
mixed with data from current iteration. But when I compute sum of array
elements than everything is transferred correctly (at least in tests so
far). I'll test it further, I don't know what to conclude yet.

Katja

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