From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45412) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wj9nw-00022c-6P for qemu-devel@nongnu.org; Sat, 10 May 2014 12:07:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Wj9np-00018Z-Vt for qemu-devel@nongnu.org; Sat, 10 May 2014 12:07:16 -0400 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:41189 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wj9np-00018C-Lp for qemu-devel@nongnu.org; Sat, 10 May 2014 12:07:09 -0400 Message-ID: <536E4EA8.6090800@kamp.de> Date: Sat, 10 May 2014 18:07:04 +0200 From: Peter Lieven MIME-Version: 1.0 References: <1399719075-11517-1-git-send-email-pl@kamp.de> <536E46C3.1050502@redhat.com> In-Reply-To: <536E46C3.1050502@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] migration: cache memory region ram ptr List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , qemu-devel@nongnu.org Cc: dgilbert@redhat.com, quintela@redhat.com You mean, a) extent the MemoryRegion stuct with a pointer? b) on the first call to memory_region_get_ram_ptr cache the result in the struct? Peter Am 10.05.2014 17:33, schrieb Paolo Bonzini: > Il 10/05/2014 12:51, Peter Lieven ha scritto: >> we currently look up the ram ptr for each single page. Cache >> the pointer while we operate on the same block. > > Why don't you instead cache the result in the MemoryRegion, so that memory_region_get_ram_ptr becomes a simple, inline field access? > > Paolo > >> Signed-off-by: Peter Lieven >> --- >> arch_init.c | 23 ++++++++++++++++------- >> 1 file changed, 16 insertions(+), 7 deletions(-) >> >> diff --git a/arch_init.c b/arch_init.c >> index 582b716..ce338aa 100644 >> --- a/arch_init.c >> +++ b/arch_init.c >> @@ -594,13 +594,19 @@ static int ram_save_block(QEMUFile *f, bool last_stage) >> ram_bulk_stage = false; >> } >> } else { >> + static uint8_t *ram_ptr; >> int ret; >> uint8_t *p; >> bool send_async = true; >> - int cont = (block == last_sent_block) ? >> - RAM_SAVE_FLAG_CONTINUE : 0; >> + int cont = 0; >> >> - p = memory_region_get_ram_ptr(mr) + offset; >> + if (block != last_sent_block) { >> + ram_ptr = memory_region_get_ram_ptr(mr); >> + } else { >> + cont = RAM_SAVE_FLAG_CONTINUE; >> + } >> + >> + p = ram_ptr + offset; >> >> /* In doubt sent page as normal */ >> bytes_sent = -1; >> @@ -990,16 +996,17 @@ static inline void *host_from_stream_offset(QEMUFile *f, >> int flags) >> { >> static RAMBlock *block = NULL; >> + static uint8_t *ram_ptr; >> char id[256]; >> uint8_t len; >> >> if (flags & RAM_SAVE_FLAG_CONTINUE) { >> - if (!block) { >> + if (!block || !ram_ptr) { >> fprintf(stderr, "Ack, bad migration stream!\n"); >> return NULL; >> } >> >> - return memory_region_get_ram_ptr(block->mr) + offset; >> + return ram_ptr + offset; >> } >> >> len = qemu_get_byte(f); >> @@ -1007,8 +1014,10 @@ static inline void *host_from_stream_offset(QEMUFile *f, >> id[len] = 0; >> >> QTAILQ_FOREACH(block, &ram_list.blocks, next) { >> - if (!strncmp(id, block->idstr, sizeof(id))) >> - return memory_region_get_ram_ptr(block->mr) + offset; >> + if (!strncmp(id, block->idstr, sizeof(id))) { >> + ram_ptr = memory_region_get_ram_ptr(block->mr); >> + return ram_ptr + offset; >> + } >> } >> >> fprintf(stderr, "Can't find block %s!\n", id); >> >