Message ID | 1273669964-29783-1-git-send-email-Pierre.Riteau@irisa.fr |
---|---|
State | New |
Headers | show |
Anyone interested by this diff? On 12 mai 2010, at 15:12, 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 <Pierre.Riteau@irisa.fr> > --- > 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); > } > -- > 1.7.1 > >
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<Pierre.Riteau@irisa.fr> > 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); > } >
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); }
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 <Pierre.Riteau@irisa.fr> --- arch_init.c | 21 ++++++++++++--------- 1 files changed, 12 insertions(+), 9 deletions(-)