From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:38181) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIevm-0006XH-K9 for qemu-devel@nongnu.org; Thu, 21 Mar 2013 08:49:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UIevl-0004lk-2N for qemu-devel@nongnu.org; Thu, 21 Mar 2013 08:49:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:26871) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIevk-0004lP-R4 for qemu-devel@nongnu.org; Thu, 21 Mar 2013 08:49:17 -0400 Message-ID: <514B0212.8010706@redhat.com> Date: Thu, 21 Mar 2013 14:50:26 +0200 From: Orit Wasserman MIME-Version: 1.0 References: <1363856971-4601-1-git-send-email-owasserm@redhat.com> <1363856971-4601-8-git-send-email-owasserm@redhat.com> <514AD93E.1090205@redhat.com> <514AEAB0.2000108@redhat.com> <20130321111427.GD24024@redhat.com> In-Reply-To: <20130321111427.GD24024@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC 07/12] Store the data to send also in iovec List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Paolo Bonzini , chegu_vinod@hp.com, qemu-devel@nongnu.org, quintela@redhat.com On 03/21/2013 01:14 PM, Michael S. Tsirkin wrote: > On Thu, Mar 21, 2013 at 01:10:40PM +0200, Orit Wasserman wrote: >> On 03/21/2013 11:56 AM, Paolo Bonzini wrote: >>> Il 21/03/2013 10:09, Orit Wasserman ha scritto: >>>> All data is still copied into the static buffer. >>>> >>>> Signed-off-by: Orit Wasserman >>>> --- >>>> savevm.c | 13 +++++++++++-- >>>> 1 file changed, 11 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/savevm.c b/savevm.c >>>> index ec64533..d5834ca 100644 >>>> --- a/savevm.c >>>> +++ b/savevm.c >>>> @@ -114,6 +114,7 @@ void qemu_announce_self(void) >>>> /* savevm/loadvm support */ >>>> >>>> #define IO_BUF_SIZE 32768 >>>> +#define MAX_IOV_SIZE 64 >>> >>> You could use IOV_MAX, or min(IOV_MAX, 64). >> Sure >> The 64 should be tuned on a >>> good 10G network... >> >> You need to remember that iovec of 64 is equivalent to 32 guest pages which are >> 128K data. This is a large TCP packet that will be fragmented even with jumbo frames. >> I can make it configurable but not sure if it will be useful. >> Micheal, what do you think? >> >> Orit > > You are both right :). 64 looks like a sane value, and we can > try and tune it some more if we have the time. > Paolo, are you ok with leaving it MIN(IOV_MAX, 64) at the moment? Later we can make it changeable. Orit >>> >>> Paolo >>> >>>> struct QEMUFile { >>>> const QEMUFileOps *ops; >>>> @@ -129,6 +130,9 @@ struct QEMUFile { >>>> int buf_size; /* 0 when writing */ >>>> uint8_t buf[IO_BUF_SIZE]; >>>> >>>> + struct iovec iov[MAX_IOV_SIZE]; >>>> + unsigned int iovcnt; >>>> + >>>> int last_error; >>>> }; >>>> >>>> @@ -546,6 +550,7 @@ static void qemu_fflush(QEMUFile *f) >>>> f->pos += f->buf_index; >>>> } >>>> f->buf_index = 0; >>>> + f->iovcnt = 0; >>>> } >>>> if (ret < 0) { >>>> qemu_file_set_error(f, ret); >>>> @@ -638,12 +643,14 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size) >>>> if (l > size) >>>> l = size; >>>> memcpy(f->buf + f->buf_index, buf, l); >>>> + f->iov[f->iovcnt].iov_base = f->buf + f->buf_index; >>>> + f->iov[f->iovcnt++].iov_len = l; >>>> f->is_write = 1; >>>> f->buf_index += l; >>>> f->bytes_xfer += l; >>>> buf += l; >>>> size -= l; >>>> - if (f->buf_index >= IO_BUF_SIZE) { >>>> + if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) { >>>> qemu_fflush(f); >>>> if (qemu_file_get_error(f)) { >>>> break; >>>> @@ -667,8 +674,10 @@ void qemu_put_byte(QEMUFile *f, int v) >>>> f->buf[f->buf_index++] = v; >>>> f->is_write = 1; >>>> f->bytes_xfer += 1; >>>> + f->iov[f->iovcnt].iov_base = f->buf + (f->buf_index - 1); >>>> + f->iov[f->iovcnt++].iov_len = 1; >>>> >>>> - if (f->buf_index >= IO_BUF_SIZE) { >>>> + if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) { >>>> qemu_fflush(f); >>>> } >>>> } >>>> >>>