On 01/08/2012 03:58 PM, Takuya Yoshikawa wrote:
> Check how long it takes to get dirty log according to the number of
> dirty pages, like:
>
> get dirty log: 49 us for 1 dirty pages
> get dirty log: 49 us for 2 dirty pages
> get dirty log: 45 us for 4 dirty pages
> get dirty log: 41 us for 8 dirty pages
> get dirty log: 40 us for 16 dirty pages
> get dirty log: 44 us for 32 dirty pages
> get dirty log: 39 us for 64 dirty pages
> get dirty log: 42 us for 128 dirty pages
> get dirty log: 45 us for 256 dirty pages
> get dirty log: 53 us for 512 dirty pages
> get dirty log: 72 us for 1024 dirty pages
> get dirty log: 99 us for 2048 dirty pages
> get dirty log: 132 us for 4096 dirty pages
> get dirty log: 224 us for 8192 dirty pages
> get dirty log: 383 us for 16384 dirty pages
> get dirty log: 725 us for 32768 dirty pages
> get dirty log: 1412 us for 65536 dirty pages
> get dirty log: 2746 us for 131072 dirty pages
> get dirty log: 5455 us for 262144 dirty pages
Nice!
> +
> +void write_mem(volatile bool& running, volatile int& nr_dirty_pages,
> + void* logged_slot_virt)
> +{
> + while (nr_dirty_pages >= 0) {
> + char* var = static_cast<char*>(logged_slot_virt);
> +
> + while (!running) {
> + delay_loop(1000);
> + }
> + for (int i = 0; i < nr_dirty_pages; ++i) {
> + ++(*var);
> + var += page_size;
> + }
> + running = false;
You use running both to start this loop, and signal its end. Better to
use two variables.
But why use threads at all? Just call this before reading the dirty
log, no need for synchronization.
> + }
> +}
> +
> +void check_dirty_log(mem_slot& slot,
> + volatile bool& running,
> + volatile int& nr_dirty_pages)
> +{
> + slot.set_dirty_logging(true);
> + slot.update_dirty_log();
> +
> + for (int i = 1; i <= nr_pages; i *= 2) {
> + struct timeval start_time, end_time;
> + long time_usec;
> +
> + nr_dirty_pages = i;
> + running = true;
> + // wait until the guest finishes writing
> + while (running) {
> + delay_loop(1000);
> + }
> +
> + gettimeofday(&start_time, NULL);
> + slot.update_dirty_log();
> + gettimeofday(&end_time, NULL);
Nicer to have a function that returns time in nanoseconds.
> +
> + time_usec = 1000 * 1000 * (end_time.tv_sec - start_time.tv_sec);
> + time_usec += end_time.tv_usec - start_time.tv_usec;
> + printf("get dirty log: %6ld us for %10d dirty pages\n",
> + time_usec, nr_dirty_pages);
> + }
> +
> + // stop the guest
> + nr_dirty_pages = -1;
> + running = true;
> + slot.set_dirty_logging(false);
> +}
> +
> +}
> +
>
--
error compiling committee.c: too many arguments to function
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