From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=50111 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OJWVj-0000ym-71 for qemu-devel@nongnu.org; Tue, 01 Jun 2010 14:48:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OJWGP-0006m8-8e for qemu-devel@nongnu.org; Tue, 01 Jun 2010 14:32:34 -0400 Received: from mail-gw0-f45.google.com ([74.125.83.45]:36794) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OJWGP-0006lu-5F for qemu-devel@nongnu.org; Tue, 01 Jun 2010 14:32:33 -0400 Received: by gwb11 with SMTP id 11so3869169gwb.4 for ; Tue, 01 Jun 2010 11:32:32 -0700 (PDT) Message-ID: <4C0550E8.80700@codemonkey.ws> Date: Tue, 01 Jun 2010 13:26:48 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH 2/2] migration: Fix calculation of bytes_transferred References: <1273669964-29783-1-git-send-email-Pierre.Riteau@irisa.fr> In-Reply-To: <1273669964-29783-1-git-send-email-Pierre.Riteau@irisa.fr> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Pierre Riteau Cc: qemu-devel@nongnu.org On 05/12/2010 08:12 AM, Pierre Riteau wrote: > When a page with all identical bytes is transferred, it is counted > as a full page (TARGET_PAGE_SIZE) although only one byte is actually > sent. Fix this by changing ram_save_block() to return the number of > bytes sent instead of a boolean value. This makes bandwidth > estimation, and consequently downtime estimation, more precise. > > Signed-off-by: Pierre Riteau > Applied. Thanks. Regards, Anthony Liguori > --- > arch_init.c | 21 ++++++++++++--------- > 1 files changed, 12 insertions(+), 9 deletions(-) > > diff --git a/arch_init.c b/arch_init.c > index cf6b7b0..76317af 100644 > --- a/arch_init.c > +++ b/arch_init.c > @@ -108,7 +108,7 @@ static int ram_save_block(QEMUFile *f) > static ram_addr_t current_addr = 0; > ram_addr_t saved_addr = current_addr; > ram_addr_t addr = 0; > - int found = 0; > + int bytes_sent = 0; > > while (addr< last_ram_offset) { > if (cpu_physical_memory_get_dirty(current_addr, MIGRATION_DIRTY_FLAG)) { > @@ -123,19 +123,20 @@ static int ram_save_block(QEMUFile *f) > if (is_dup_page(p, *p)) { > qemu_put_be64(f, current_addr | RAM_SAVE_FLAG_COMPRESS); > qemu_put_byte(f, *p); > + bytes_sent = 1; > } else { > qemu_put_be64(f, current_addr | RAM_SAVE_FLAG_PAGE); > qemu_put_buffer(f, p, TARGET_PAGE_SIZE); > + bytes_sent = TARGET_PAGE_SIZE; > } > > - found = 1; > break; > } > addr += TARGET_PAGE_SIZE; > current_addr = (saved_addr + addr) % last_ram_offset; > } > > - return found; > + return bytes_sent; > } > > static uint64_t bytes_transferred; > @@ -206,11 +207,11 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque) > bwidth = qemu_get_clock_ns(rt_clock); > > while (!qemu_file_rate_limit(f)) { > - int ret; > + int bytes_sent; > > - ret = ram_save_block(f); > - bytes_transferred += ret * TARGET_PAGE_SIZE; > - if (ret == 0) { /* no more blocks */ > + bytes_sent = ram_save_block(f); > + bytes_transferred += bytes_sent; > + if (bytes_sent == 0) { /* no more blocks */ > break; > } > } > @@ -226,9 +227,11 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque) > > /* try transferring iterative blocks of memory */ > if (stage == 3) { > + int bytes_sent; > + > /* flush all remaining blocks regardless of rate limiting */ > - while (ram_save_block(f) != 0) { > - bytes_transferred += TARGET_PAGE_SIZE; > + while ((bytes_sent = ram_save_block(f)) != 0) { > + bytes_transferred += bytes_sent; > } > cpu_physical_memory_set_dirty_tracking(0); > } >