Re: [PATCH v9 1/3] migration/dirtyrate: implement vCPU dirtyrate calculation periodically

[Peter Xu]

On Fri, Dec 03, 2021 at 09:39:45AM +0800, huangy81@chinatelecom.cn wrote:
> +static void dirtylimit_calc_func(void)
> +{
> +    CPUState *cpu;
> +    DirtyPageRecord *dirty_pages;
> +    int64_t start_time, end_time, calc_time;
> +    DirtyRateVcpu rate;
> +    int i = 0;
> +
> +    dirty_pages = g_malloc0(sizeof(*dirty_pages) *
> +        dirtylimit_calc_state->data.nvcpu);
> +
> +    CPU_FOREACH(cpu) {
> +        record_dirtypages(dirty_pages, cpu, true);
> +    }
> +
> +    start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
> +    g_usleep(DIRTYLIMIT_CALC_TIME_MS * 1000);
> +    end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
> +    calc_time = end_time - start_time;
> +
> +    qemu_mutex_lock_iothread();
> +    memory_global_dirty_log_sync();
> +    qemu_mutex_unlock_iothread();
> +
> +    CPU_FOREACH(cpu) {
> +        record_dirtypages(dirty_pages, cpu, false);
> +    }
> +
> +    for (i = 0; i < dirtylimit_calc_state->data.nvcpu; i++) {
> +        uint64_t increased_dirty_pages =
> +            dirty_pages[i].end_pages - dirty_pages[i].start_pages;
> +        uint64_t memory_size_MB =
> +            (increased_dirty_pages * TARGET_PAGE_SIZE) >> 20;
> +        int64_t dirtyrate = (memory_size_MB * 1000) / calc_time;
> +
> +        rate.id = i;
> +        rate.dirty_rate  = dirtyrate;
> +        dirtylimit_calc_state->data.rates[i] = rate;
> +
> +        trace_dirtyrate_do_calculate_vcpu(i,
> +            dirtylimit_calc_state->data.rates[i].dirty_rate);
> +    }
> +}

This looks so like the calc-dirty-rate code already.

I think adding a new resion (GLOBAL_DIRTY_LIMIT) is fine, however still, any
chance to merge the code?

-- 
Peter Xu