From mboxrd@z Thu Jan 1 00:00:00 1970 From: OHMURA Kei Subject: [PATCH v2] qemu-kvm: Speed up of the dirty-bitmap-traveling Date: Wed, 10 Feb 2010 19:52:41 +0900 Message-ID: <4B728FF9.6010707@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Cc: Avi Kivity , mtosatti@redhat.com, ohmura.kei@lab.ntt.co.jp To: "kvm@vger.kernel.org" , "qemu-devel@nongnu.org" Return-path: Received: from tama500.ecl.ntt.co.jp ([129.60.39.148]:40986 "EHLO tama500.ecl.ntt.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752726Ab0BJKw7 (ORCPT ); Wed, 10 Feb 2010 05:52:59 -0500 Sender: kvm-owner@vger.kernel.org List-ID: dirty-bitmap-traveling is carried out by byte size in qemu-kvm.c. But We think that dirty-bitmap-traveling by long size is faster than by byte size especially when most of memory is not dirty. Signed-off-by: OHMURA Kei --- bswap.h | 1 - qemu-kvm.c | 30 ++++++++++++++++-------------- 2 files changed, 16 insertions(+), 15 deletions(-) diff --git a/bswap.h b/bswap.h index 4558704..d896f01 100644 --- a/bswap.h +++ b/bswap.h @@ -209,7 +209,6 @@ static inline void cpu_to_be32wu(uint32_t *p, uint32_t v) #define cpu_to_32wu cpu_to_le32wu #endif -#undef le_bswap #undef be_bswap #undef le_bswaps #undef be_bswaps diff --git a/qemu-kvm.c b/qemu-kvm.c index a305907..ea07912 100644 --- a/qemu-kvm.c +++ b/qemu-kvm.c @@ -2438,27 +2438,29 @@ static int kvm_get_dirty_pages_log_range(unsigned long start_addr, unsigned long offset, unsigned long mem_size) { - unsigned int i, j, n = 0; - unsigned char c; - unsigned long page_number, addr, addr1; + unsigned int i, j; + unsigned long page_number, addr, addr1, c; ram_addr_t ram_addr; - unsigned int len = ((mem_size / TARGET_PAGE_SIZE) + 7) / 8; + unsigned int len = ((mem_size / TARGET_PAGE_SIZE) + HOST_LONG_BITS - 1) / + HOST_LONG_BITS; + unsigned long *bitmap_ul = (unsigned long *)bitmap; /* * bitmap-traveling is faster than memory-traveling (for addr...) * especially when most of the memory is not dirty. */ for (i = 0; i < len; i++) { - c = bitmap[i]; - while (c > 0) { - j = ffsl(c) - 1; - c &= ~(1u << j); - page_number = i * 8 + j; - addr1 = page_number * TARGET_PAGE_SIZE; - addr = offset + addr1; - ram_addr = cpu_get_physical_page_desc(addr); - cpu_physical_memory_set_dirty(ram_addr); - n++; + if (bitmap_ul[i] != 0) { + c = le_bswap(bitmap_ul[i], HOST_LONG_BITS); + while (c > 0) { + j = ffsl(c) - 1; + c &= ~(1ul << j); + page_number = i * HOST_LONG_BITS + j; + addr1 = page_number * TARGET_PAGE_SIZE; + addr = offset + addr1; + ram_addr = cpu_get_physical_page_desc(addr); + cpu_physical_memory_set_dirty(ram_addr); + } } } return 0; -- 1.6.3.3