By: Heikki Kultala (hkultala.delete@this.iki.NOSPAM.fi), April 20, 2011 8:24 pm
Room: Moderated Discussions
EduardoS (no@spam.com) on 4/20/11 wrote:
---------------------------
>Heikki Kultala (hkultala@iki.NOSPAM.fi) on 4/20/11 wrote:
>---------------------------
>>If memory operation is being handled, no ALU operations can execute at same time
>>on ATI.
>
>No, memory operations are executed on a different part of the chip,
yes
> it's like a memory operations only core, the ALUs are free to execute instructions of other threads in this time.
.. but no, at least with texture fetches.
Texture fetches consume the execution slots of the instruction word, ALU operations cannot be started at same cycle.
>
>>But if the code does not have any ILP, only parallelism between work items, then
>>3/4 or those ATI ALU's are idling. This practically means badly optimized code.
>
>Do 2 to 4 work itens per lane and you will find ILP, it's SIMD after all, right?
>Just sad AMD compiler can't do this (and a lot fo other important things) alone...
>
---------------------------
>Heikki Kultala (hkultala@iki.NOSPAM.fi) on 4/20/11 wrote:
>---------------------------
>>If memory operation is being handled, no ALU operations can execute at same time
>>on ATI.
>
>No, memory operations are executed on a different part of the chip,
yes
> it's like a memory operations only core, the ALUs are free to execute instructions of other threads in this time.
.. but no, at least with texture fetches.
Texture fetches consume the execution slots of the instruction word, ALU operations cannot be started at same cycle.
>
>>But if the code does not have any ILP, only parallelism between work items, then
>>3/4 or those ATI ALU's are idling. This practically means badly optimized code.
>
>Do 2 to 4 work itens per lane and you will find ILP, it's SIMD after all, right?
>Just sad AMD compiler can't do this (and a lot fo other important things) alone...
>
Topic | Posted By | Date |
---|---|---|
New Article: Predicting GPU Performance for AMD and Nvidia | David Kanter | 2011/04/12 12:55 AM |
Graph is not red-green colorblind friendly (NT) | RatherNotSay | 2011/04/12 04:51 AM |
Fixed | David Kanter | 2011/04/12 09:46 AM |
New Article: Predicting GPU Performance for AMD and Nvidia | James | 2011/04/12 01:30 PM |
New Article: Predicting GPU Performance for AMD and Nvidia | David Kanter | 2011/04/12 03:51 PM |
Try HD6450 or HD6850 | EduardoS | 2011/04/12 04:31 PM |
Try HD6450 or HD6850 | David Kanter | 2011/04/13 11:25 AM |
Try HD6450 or HD6850 | EduardoS | 2011/04/13 04:20 PM |
of cause | Moritz | 2011/04/14 09:03 AM |
of cause | EduardoS | 2011/04/14 02:55 PM |
Barts = 5D | Moritz | 2011/04/14 10:26 PM |
Barts = 5D | Antti-Ville Tuunainen | 2011/04/15 01:38 AM |
Limiting fixed function units | Moritz | 2011/04/15 05:28 AM |
Limiting fixed function units | Vincent Diepeveen | 2011/04/20 03:38 AM |
lack of detail | Moritz | 2011/04/20 10:24 AM |
lack of detail | EduardoS | 2011/04/20 12:45 PM |
gpgpu | Vincent Diepeveen | 2011/04/16 03:10 AM |
gpgpu | EduardoS | 2011/04/17 01:31 PM |
gpgpu | Groo | 2011/04/17 01:58 PM |
gpgpu | EduardoS | 2011/04/17 02:08 PM |
gpgpu | Ian Ameline | 2011/04/18 04:55 PM |
gpgpu | Ping-Che Chen | 2011/04/19 01:59 AM |
GPU numerical compliance | Sylvain Collange | 2011/04/19 12:38 PM |
GPU numerical compliance | Vincent Diepeveen | 2011/04/20 03:17 AM |
gpgpu | Vincent Diepeveen | 2011/04/20 03:02 AM |
gpgpu and core counts | Heikki Kultala | 2011/04/20 05:41 AM |
gpgpu and core counts | Vincent Diepeveen | 2011/04/20 06:52 AM |
gpgpu and core counts | none | 2011/04/20 08:05 AM |
gpgpu and core counts | EduardoS | 2011/04/20 12:36 PM |
gpgpu and core counts | Heikki Kultala | 2011/04/20 11:16 AM |
gpgpu and core counts | EduardoS | 2011/04/20 12:34 PM |
gpgpu and core counts | Heikki Kultala | 2011/04/20 08:24 PM |
gpgpu and core counts | EduardoS | 2011/04/20 09:55 PM |
gpgpu and core counts | Heikki Kultala | 2011/04/21 07:48 AM |
gpgpu and core counts | EduardoS | 2011/04/22 02:41 PM |
AMD Compute and Texture Fetch | David Kanter | 2011/04/21 11:42 AM |
AMD Compute and Texture Fetch | Vincent Diepeveen | 2011/04/22 02:14 AM |
AMD Compute and Texture Fetch | David Kanter | 2011/04/22 11:53 AM |
AMD Compute and Texture Fetch | EduardoS | 2011/04/22 02:46 PM |
AMD Compute and Texture Fetch | David Kanter | 2011/04/22 03:02 PM |
AMD Compute and Texture Fetch | EduardoS | 2011/04/22 03:18 PM |
AMD Compute and Texture Fetch | anon | 2011/04/22 04:30 PM |
AMD Compute and Texture Fetch | David Kanter | 2011/04/22 10:17 PM |
gpgpu and core counts | Vincent Diepeveen | 2011/04/20 01:12 PM |
gpgpu and core counts | Heikki Kultala | 2011/04/21 11:23 AM |
gpgpu and core counts | Vincent Diepeveen | 2011/04/22 03:11 AM |
Keep the crazy politics out of this | David Kanter | 2011/04/22 09:39 AM |
Keep the crazy politics out of this | Vincent Diepeveen | 2011/04/22 10:12 AM |
Keep the crazy politics out of this | David Kanter | 2011/04/22 11:44 AM |
gpgpu and core counts | Jouni Osmala | 2011/04/22 12:06 PM |
gpgpu | EduardoS | 2011/04/20 12:59 PM |
gpgpu | Vincent Diepeveen | 2011/04/20 01:37 PM |
gpgpu | EduardoS | 2011/04/20 06:27 PM |
gpgpu | Vincent Diepeveen | 2011/04/21 03:06 AM |
gpgpu | EduardoS | 2011/04/22 03:00 PM |
New Article: Predicting GPU Performance for AMD and Nvidia | PiedPiper | 2011/04/12 11:05 PM |
New Article: Predicting GPU Performance for AMD and Nvidia | David Kanter | 2011/04/12 11:42 PM |
New Article: Predicting GPU Performance for AMD and Nvidia | MS | 2011/04/15 06:04 AM |
New Article: Predicting GPU Performance for AMD and Nvidia | Kevin G | 2011/04/16 03:25 AM |
New Article: Predicting GPU Performance for AMD and Nvidia | David Kanter | 2011/04/16 09:42 AM |
New Article: Predicting GPU Performance for AMD and Nvidia | Vincent Diepeveen | 2011/04/20 03:20 AM |
memory | Moritz | 2011/04/14 10:03 PM |
memory - more | Moritz | 2011/04/16 12:11 AM |
New Article: Predicting GPU Performance for AMD and Nvidia | Kevin G | 2011/04/14 12:30 PM |