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[PATCH v5 09/10] Add the function of colo_bitmap_clear_dirty
From: |
leirao |
Subject: |
[PATCH v5 09/10] Add the function of colo_bitmap_clear_dirty |
Date: |
Thu, 1 Apr 2021 15:47:28 +0800 |
From: "Rao, Lei" <lei.rao@intel.com>
When we use continuous dirty memory copy for flushing ram cache on
secondary VM, we can also clean up the bitmap of contiguous dirty
page memory. This also can reduce the VM stop time during checkpoint.
The performance test for COLO as follow:
Server configuraton:
CPU :Intel(R) Xeon(R) Gold 6140 CPU @ 2.30GHz
MEM :251G(type:DDR4 Speed:2666 MT/s)
SSD :Intel 730 and DC S35x0/3610/3700 Series SSDs
dirty pages:3189376 migration_bitmap_clear_dirty time consuming(ns):105194000
dirty pages:3189784 migration_bitmap_clear_dirty time consuming(ns):105297000
dirty pages:3190501 migration_bitmap_clear_dirty time consuming(ns):105410000
dirty pages:3188734 migration_bitmap_clear_dirty time consuming(ns):105138000
dirty pages:3189464 migration_bitmap_clear_dirty time consuming(ns):111736000
dirty pages:3188558 migration_bitmap_clear_dirty time consuming(ns):105079000
dirty pages:3239489 migration_bitmap_clear_dirty time consuming(ns):106761000
dirty pages:3190240 colo_bitmap_clear_dirty time consuming(ns):8369000
dirty pages:3189293 colo_bitmap_clear_dirty time consuming(ns):8388000
dirty pages:3189171 colo_bitmap_clear_dirty time consuming(ns):8641000
dirty pages:3189099 colo_bitmap_clear_dirty time consuming(ns):8280000
dirty pages:3189974 colo_bitmap_clear_dirty time consuming(ns):8352000
dirty pages:3189471 colo_bitmap_clear_dirty time consuming(ns):8348000
dirty pages:3189681 colo_bitmap_clear_dirty time consuming(ns):8426000
it can be seen from the data that colo_bitmap_clear_dirty is more
efficient.
Signed-off-by: Lei Rao <lei.rao@intel.com>
---
migration/ram.c | 36 +++++++++++++++++++++++++++++++-----
1 file changed, 31 insertions(+), 5 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index 317fa4e..570ffa4 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -857,6 +857,36 @@ unsigned long colo_bitmap_find_dirty(RAMState *rs,
RAMBlock *rb,
return first;
}
+/**
+ * colo_bitmap_clear_dirty:when we flush ram cache to ram, we will use
+ * continuous memory copy, so we can also clean up the bitmap of contiguous
+ * dirty memory.
+ */
+static inline bool colo_bitmap_clear_dirty(RAMState *rs,
+ RAMBlock *rb,
+ unsigned long start,
+ unsigned long num)
+{
+ bool ret;
+ unsigned long i = 0;
+
+ /*
+ * Since flush ram cache to ram can only happen on Secondary VM.
+ * and the clear bitmap always is NULL on destination side.
+ * Therefore, there is unnecessary to judge whether the
+ * clear_bitmap needs clear.
+ */
+ QEMU_LOCK_GUARD(&rs->bitmap_mutex);
+ for (i = 0; i < num; i++) {
+ ret = test_and_clear_bit(start + i, rb->bmap);
+ if (ret) {
+ rs->migration_dirty_pages--;
+ }
+ }
+
+ return ret;
+}
+
static inline bool migration_bitmap_clear_dirty(RAMState *rs,
RAMBlock *rb,
unsigned long page)
@@ -3723,11 +3753,7 @@ void colo_flush_ram_cache(void)
num = 0;
block = QLIST_NEXT_RCU(block, next);
} else {
- unsigned long i = 0;
-
- for (i = 0; i < num; i++) {
- migration_bitmap_clear_dirty(ram_state, block, offset + i);
- }
+ colo_bitmap_clear_dirty(ram_state, block, offset, num);
dst_host = block->host
+ (((ram_addr_t)offset) << TARGET_PAGE_BITS);
src_host = block->colo_cache
--
1.8.3.1
- [PATCH v5 03/10] Optimize the function of filter_send, (continued)
- [PATCH v5 03/10] Optimize the function of filter_send, leirao, 2021/04/01
- [PATCH v5 04/10] Remove migrate_set_block_enabled in checkpoint, leirao, 2021/04/01
- [PATCH v5 05/10] Add a function named packet_new_nocopy for COLO., leirao, 2021/04/01
- [PATCH v5 06/10] Add the function of colo_compare_cleanup, leirao, 2021/04/01
- [PATCH v5 07/10] Reset the auto-converge counter at every checkpoint., leirao, 2021/04/01
- [PATCH v5 08/10] Reduce the PVM stop time during Checkpoint, leirao, 2021/04/01
- [PATCH v5 09/10] Add the function of colo_bitmap_clear_dirty,
leirao <=
- [PATCH v5 10/10] Fixed calculation error of pkt->header_size in fill_pkt_tcp_info(), leirao, 2021/04/01
- Re: [PATCH v5 00/10] Fixed some bugs and optimized some codes for COLO, Lukas Straub, 2021/04/04