Asif Lodhi wrote: > Hi John, > > On 5/7/08, John Beardmore <John at t4sltd.co.uk> wrote: >> Asif Lodhi wrote: >>> Though I don't know how to do it using Linux but, if you're using >>> WinXP, you can distribute each process' load equally on ALL the cores >>> from the Task Manager >> But if the task is single threaded, can that help ? > > May be. As it is the operating system (XP in this case) that schedules > and allocates all the jobs to whatever cores you have in your > processor. Though I have yet to study Intel's multi-core processor > achitecture, I think it's about parallelization and re-arrangement > (for better optimized execution) of machine instructions "inside" the > processor. And, though I have yet to investigate how the generated > multi-threading code (i.e. assembly/machine language code generated > from C/C++, for example) looks like but I DO know that Intel > processors have tasks scheduling instructions at the machine language > level at least since Intel's 80386 processor. This means that all the > threading primitives that, for example, Windows and Linux, provide at > the operating system level obviously make use of those > processor-provided threading primitives internally. I personally think > that multiple core technology is currently being used by the OS to > "interally" parallelize the instruction execution inside the same > processor at the same time. > >>> (just right click on any process in the task >>> manager and you'll see the option) OR you can also allocate processes >>> on a per core basis (same option just remove the check from the cores >>> that you want to allocate to other tasks than the one you're >>> focusing). >> Does this work on XP pro ? > > YES. ABSOLUTELY. But I guess you'll notice the difference in > graphically intensive applications such as Photoshop, etc. You CAN > allocate a single-threaded application one or more cores as I earlier > said. By default, XP seems to allocate all processor to all the cores. > Of course, assigning fewer cores to a software application process > means less performance. You can use it to assign fewer cores to > low-priority applications and all the cores to higher-priority > applications. > > In addition, you can even change the priority of a running process > from the process tab of the Windows XP task manager - just right click > on any process and select "Set Priority" to change the current > priority. > >> To what extent is the exploitation of multi core technology on the road >> maps for these ? Photoshop perhaps ? > > I have noticed "tremendous" speed boost in highly graphic intensive > applications on my Intel Core Duo 2 2.6 GHz machine with 2GB RAM > even though I am still using the old IDE based hard disks - not SATA. > In your case, it absolutely means a visibile gain in Photoshop > performance. But I would say that the "mother board" and the > components used to build the board also matter a lot. That's why I > earlier provided a list of related hardware websites that you can use > to review the various hardware components, computers, etc.
OK, but I thought Photoshop had had code to exploit dual processor systems for years ? If so, it can presumably handle multiple cores ? >> Further, in many systems, is CPU the bottle neck, or memory >> bandwidth ? > > Compute-intensive applications such as Blender, Photoshop raster > operations/filters, Inkscape bitmap trace (autotrace or potrace), etc. > are CPU hogs. So more RAW CPU power is nice to have when using these > applications. Also, many Java desktop applications are CPU hogs when > performing most of the operations. I've always noticed visibly > substantial difference in Java speed whenever I've upgraded. Hmmm... Years ago I was involved in writing a market research application that everybody thought was a CPU hog. We started off with 20MHz 386 CPUs, then upgraded to 33MHz. From memory, it ran about 12% faster. Given that disk use didn't seem to be an issue, we concluded at the time that it was probably limited by memory access. > Use the "Performance" tab of the Windows XP Task Manager to find out > if you need more memory. If the PF Usage (Page File Usage) is GREATER > than zero then it means that Windows XP is using the page file (a disk > file to store temporarily store memory contents) as an extension of > your main memory - because of your higher memory requirements. This is > a very good indicator as to how much more memory you actually need. > Increase your memory and you'll only seldom see the PF usage greater > than zero - only when you use many applications at the same time that > collectively use more memory than available, that is. > > You can view the memory, CPU requirements of EACH application/process > using the Windows Task Manager. Run Task Manager, switch to the > "Process" tab, select "View/Select Columns" from the Task Manager's > menu bar and then select > > CPU Usage > Memory Usage > Page Faults > Virtual Memory Size > Thread Count > > from the list to include these columns in the "Process" tab view of > your Task Manager - re-size the task manager's window appropriately > wider to see all the columns. You can also SORT various columsn in > ascending or descending order. > > More memory is always nice to have. Even if the applications that you > use don't use much memory, the extra memory can be used to run many > applications at the same time. :) Yes - already doing that. > You can always add more memory if you > notice in Task Manager that some applications that are important to > use have a higher memory usage and higher page faults, for example. > Check out the "Performance" tab of the Windows XP Task Manager when, > for example, you run a compute-intensive filter in Photoshop - you > will see a sudden spike in the processor usage graph. I've got 2 gig in this machine and we seldom use more than 1.5 so I really don't think memory is a big issue. Cheers, J/. -- John Beardmore, MSc EDM (Open), B.A. Chem (Oxon), CMIOSH, AIEMA, MEI Managing Director, T4 Sustainability Limited. http://www.T4sLtd.co.uk/ Carbon Trust Consultant: Energy Audit, Carbon Footprint, Design Advice Energy Efficiency Accreditation Scheme, (EEAS), Registered Assessor Phone: 0845 4561332 Mobile: 07785 563116 Skype: t4sustainability
