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Re: [Qemu-devel] [PATCH] Change the method to calculate dirty-pages-rate
From: |
Chao Fan |
Subject: |
Re: [Qemu-devel] [PATCH] Change the method to calculate dirty-pages-rate |
Date: |
Tue, 14 Mar 2017 09:45:52 +0800 |
User-agent: |
Mutt/1.7.1 (2016-10-04) |
On Tue, Mar 14, 2017 at 09:41:30AM +0800, Li Zhijian wrote:
>
>
>On 03/14/2017 09:26 AM, Chao Fan wrote:
>> In function cpu_physical_memory_sync_dirty_bitmap, file
>> include/exec/ram_addr.h:
>>
>> if (src[idx][offset]) {
>> unsigned long bits = atomic_xchg(&src[idx][offset], 0);
>> unsigned long new_dirty;
>> new_dirty = ~dest[k];
>> dest[k] |= bits;
>> new_dirty &= bits;
>> num_dirty += ctpopl(new_dirty);
>> }
>>
>> After these codes executed, only the pages not dirtied in bitmap(dest),
>> but dirtied in dirty_memory[DIRTY_MEMORY_MIGRATION] will be calculated.
>> For example:
>> When ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION] = 0b00001111,
>> and atomic_rcu_read(&migration_bitmap_rcu)->bmap = 0b00000011,
>> the new_dirty will be 0b00001100, and this function will return 2 but not
>> 4 which is expected.
>> the dirty pages in dirty_memory[DIRTY_MEMORY_MIGRATION] are all new,
>> so these should be calculated also.
>>
>> Signed-off-by: Chao Fan <address@hidden>
>> Signed-off-by: Li Zhijian <address@hidden>
>> ---
>> include/exec/ram_addr.h | 5 ++++-
>> migration/ram.c | 7 +++----
>> 2 files changed, 7 insertions(+), 5 deletions(-)
>>
>> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
>> index cd432e7..b05dc84 100644
>> --- a/include/exec/ram_addr.h
>> +++ b/include/exec/ram_addr.h
>> @@ -355,7 +355,8 @@ static inline void
>> cpu_physical_memory_clear_dirty_range(ram_addr_t start,
>> static inline
>> uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned long *dest,
>> ram_addr_t start,
>> - ram_addr_t length)
>> + ram_addr_t length,
>> + int64_t *real_dirty_pages)
>> {
>> ram_addr_t addr;
>> unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS);
>> @@ -379,6 +380,7 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned
>> long *dest,
>> if (src[idx][offset]) {
>> unsigned long bits = atomic_xchg(&src[idx][offset], 0);
>> unsigned long new_dirty;
>> + *real_dirty_pages += ctpopl(bits);
>> new_dirty = ~dest[k];
>> dest[k] |= bits;
>> new_dirty &= bits;
>> @@ -398,6 +400,7 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned
>> long *dest,
>> start + addr,
>> TARGET_PAGE_SIZE,
>> DIRTY_MEMORY_MIGRATION)) {
>> + *real_dirty_pages += 1;
>> long k = (start + addr) >> TARGET_PAGE_BITS;
>> if (!test_and_set_bit(k, dest)) {
>> num_dirty++;
>> diff --git a/migration/ram.c b/migration/ram.c
>> index 719425b..fdf9a85 100644
>> --- a/migration/ram.c
>> +++ b/migration/ram.c
>> @@ -576,18 +576,18 @@ static inline bool
>> migration_bitmap_clear_dirty(ram_addr_t addr)
>> return ret;
>> }
>>
>> +static int64_t num_dirty_pages_period;
>> static void migration_bitmap_sync_range(ram_addr_t start, ram_addr_t length)
>> {
>> unsigned long *bitmap;
>> bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
>> - migration_dirty_pages +=
>> - cpu_physical_memory_sync_dirty_bitmap(bitmap, start, length);
>> + migration_dirty_pages += cpu_physical_memory_sync_dirty_bitmap(bitmap,
>> + start, length, &num_dirty_pages_period);
>> }
>>
>> /* Fix me: there are too many global variables used in migration process. */
>> static int64_t start_time;
>> static int64_t bytes_xfer_prev;
>> -static int64_t num_dirty_pages_period;
>> static uint64_t xbzrle_cache_miss_prev;
>> static uint64_t iterations_prev;
>>
>> @@ -648,7 +648,6 @@ static void migration_bitmap_sync(void)
>>
>> trace_migration_bitmap_sync_end(migration_dirty_pages
>> - num_dirty_pages_init);
>> - num_dirty_pages_period += migration_dirty_pages - num_dirty_pages_init;
>
>it seems num_dirty_pages_init should be removed also and update
>trace_migration_bitmap_sync_end()'s parameter.
Hi Li Zhijian,
OK, I will update and resend the V2 version.
Thanks,
Chao Fan
>
>
>Thanks
>Zhijian
>
>> end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
>>
>> /* more than 1 second = 1000 millisecons */
>>
>