yea if your processor has multiple cores or is Hyper Threading support then it can execute more than 1 instruction concurrently.
On Thu, May 6, 2010 at 12:10 AM, praba garan <prabagara...@gmail.com> wrote: > Windows Task Manager Performance tab shows the presence of two processors. > Will 2 instructions be executed concurrently?? > > With Regards, > Prabagaran. > > > > On Wed, May 5, 2010 at 4:56 PM, Varun Nagpal <varun.nagp...@gmail.com>wrote: > >> I guess with Virtual machines, instructions that simulate instructions >> of microprocessor are scheduled onto the real processor. But good >> question is how the scheduling of real microprocessor instructions >> done in a virtual machine. And the answer is again that its done on >> virtual processor, which essentially has all hardware components of >> real processor modeled in software. All sub-parts of this software >> representing essential hardware components, again run synchronously >> (in parallel) either at instruction accurate level or cycle accurate >> level. >> >> All new processor that are designed as of today, are first mostly are >> verified using simulators written in hardware description languages >> like VHDL/SystemVerilog/SystemC and then simulated either in software >> or hardware. For hardware simulation, in some cases its eventually >> possible to create them on FPGA's and verify before they are sent to >> fab lab. Its an arduous task. >> For example, you can get HDL code for free for SUN Open Sparc >> processor and can flash it on FPGA. >> >> So It doesn't really matter whether your processor is real or virtual, >> so you need to understand architecture principles and some digital >> electronics to understand at hardware(VLSI ) level >> >> Intel x86 and now x64 are the most popular architectures. Other >> popular architectures are ARM, MIPS, SPARC, PowerPC, etc. >> You should probably read the book: Computer Architecture, by hennrey >> Peterson >> >> >> On Tue, May 4, 2010 at 10:49 PM, praba garan <prabagara...@gmail.com> >> wrote: >> > I think it is necessary to study the full architecture of INTEL >> MotherBoard >> > to get a full picture. >> > How does scheduling happen incase of Virtual Machines?? >> > Then how does a packet coming to the Guest OS is sent to Guest OS. >> > ie, either directly to Guest OS or through Host OS. >> > With Regards, >> > Prabagaran. >> > >> > >> > On Mon, May 3, 2010 at 12:25 PM, Varun Nagpal <varun.nagp...@gmail.com> >> > wrote: >> >> >> >> I think its a good question and fairly complicated to explain at >> >> hardware(RTL) level. Anyways, let me give it a try : >> >> >> >> You suggested that only 1 instruction is executed by one processor, >> >> which is not true(if you have read computer architecture). Briefly, >> >> lets assume the instruction pipeline(assuming only single hardware >> >> thread) is filled with instructions from the present thread(or >> >> process) of execution. Assume number of pipeline stages to be 20. In >> >> the pipeline, 20 instructions from the current instruction control >> >> flow are executing synchronously on every clock tick. Depending upon >> >> the design of pipeline, data from registers/memory is read in >> >> different pipeline stages. Also there may also be many execution >> >> stages(ALU) before the data is written to register/memory. >> >> >> >> The OS kernel keeps a track of all the threads/processes presently >> >> executing, active, waiting, suspended etc. in memory in the form of a >> >> data structure, which is to say that it always knows the next >> >> thread/process it needs to schedule on to the processor. I think it >> >> has a compare register that stores an arbitrary number(as decided by >> >> kernel) of clock ticks for a time slice expiry and keeps another >> >> counter register to keep track of time slice expiration for present >> >> thread. At every clock tick, it increments the counter register and >> >> compares it with compare register. This summing and comparison is done >> >> by inserting an instruction in the current instruction flow. The >> >> point is that a clock interrupt is generated whenever the values of >> >> the counter and the compare registers match. When this does occur, the >> >> next PC value,registers etc(i.e its context information) is pushed >> >> onto the stack and a jump is made to an area in memory storing an >> >> interrupt vector table. I also assume that when this jump is made, the >> >> OS kernel supplies some information to the jump instruction about the >> >> next thread to be executed. This information maybe stored in another >> >> dedicated register. Now by using this information and interrupt vector >> >> table, it can find out the memory address of next thread(ii.e next >> >> instruction) to be executed. The PC including other registers is then >> >> simply loaded with context information of the new thread. >> >> >> >> Important thing here is again that when all of this is happening, the >> >> pipeline may still be executing instructions from the previous thread. >> >> In addition it will contain interrupt instructions! Only when PC is >> >> updated(in some stage of pipeline) that the instruction fetch stage >> >> will start fetching instructions from instruction memory area of new >> >> thread. In a 20 stage pipeline, it is still highly likely that it may >> >> be the case that pipeline contains instructions from old thread, >> >> followed by interrupt instruction , followed by instructions from new >> >> thread. >> >> >> >> I hope this explanation should give you better clarity. >> >> >> >> On Sun, May 2, 2010 at 7:01 PM, harit agarwal <agarwalha...@gmail.com> >> >> wrote: >> >> > although CPU is busy in exexcution...it check's its registers values >> for >> >> > the >> >> > pending interrupts .. >> >> > if any interrupt is pending at the end of the current CPU cycle...it >> >> > shedules the interrupt handler to further execute the interrupt >> >> > subroutine... >> >> > >> >> > -- >> >> > You received this message because you are subscribed to the Google >> >> > Groups >> >> > "Algorithm Geeks" group. >> >> > To post to this group, send email to algoge...@googlegroups.com. >> >> > To unsubscribe from this group, send email to >> >> > algogeeks+unsubscr...@googlegroups.com<algogeeks%2bunsubscr...@googlegroups.com> >> . >> >> > For more options, visit this group at >> >> > http://groups.google.com/group/algogeeks?hl=en. >> >> > >> >> >> >> -- >> >> You received this message because you are subscribed to the Google >> Groups >> >> "Algorithm Geeks" group. >> >> To post to this group, send email to algoge...@googlegroups.com. >> >> To unsubscribe from this group, send email to >> >> algogeeks+unsubscr...@googlegroups.com<algogeeks%2bunsubscr...@googlegroups.com> >> . >> >> For more options, visit this group at >> >> http://groups.google.com/group/algogeeks?hl=en. >> >> >> > >> > -- >> > You received this message because you are subscribed to the Google >> Groups >> > "Algorithm Geeks" group. >> > To post to this group, send email to algoge...@googlegroups.com. >> > To unsubscribe from this group, send email to >> > algogeeks+unsubscr...@googlegroups.com<algogeeks%2bunsubscr...@googlegroups.com> >> . >> > For more options, visit this group at >> > http://groups.google.com/group/algogeeks?hl=en. >> > >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Algorithm Geeks" group. >> To post to this group, send email to algoge...@googlegroups.com. >> To unsubscribe from this group, send email to >> algogeeks+unsubscr...@googlegroups.com<algogeeks%2bunsubscr...@googlegroups.com> >> . >> For more options, visit this group at >> http://groups.google.com/group/algogeeks?hl=en. >> >> > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to algoge...@googlegroups.com. > To unsubscribe from this group, send email to > algogeeks+unsubscr...@googlegroups.com<algogeeks%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. 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