| Message ID | 1278521062-13795-1-git-send-email-avi@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 07/07/2010 07:44 PM, Avi Kivity wrote: > QEMUFileBuffered stops writing when the underlying QEMUFile is not ready, > and tells its producer so. However, when the underlying QEMUFile becomes > ready, it neglects to pass that information along, resulting in stoppage > of all data until the next tick (a tenths of a second). > > Usually this doesn't matter, because most QEMUFiles used with QEMUFileBuffered > are almost always ready, but in the case of exec: migration this is not true, > due to the small pipe buffers used to connect to the target process. The > result is very slow migration. > > Fix by detecting the readiness notification and propagating it. The detection > is a little ugly since QEMUFile overloads put_buffer() to send it, but that's > the suject for a different patch. Ping.
On Tue, 03 Aug 2010 09:12:52 +0300 Avi Kivity <avi@redhat.com> wrote: > On 07/07/2010 07:44 PM, Avi Kivity wrote: > > QEMUFileBuffered stops writing when the underlying QEMUFile is not ready, > > and tells its producer so. However, when the underlying QEMUFile becomes > > ready, it neglects to pass that information along, resulting in stoppage > > of all data until the next tick (a tenths of a second). > > > > Usually this doesn't matter, because most QEMUFiles used with QEMUFileBuffered > > are almost always ready, but in the case of exec: migration this is not true, > > due to the small pipe buffers used to connect to the target process. The > > result is very slow migration. > > > > Fix by detecting the readiness notification and propagating it. The detection > > is a little ugly since QEMUFile overloads put_buffer() to send it, but that's > > the suject for a different patch. > > Ping. I've queued this fix and another one in a 'for-0.13' branch and was planning to send a pull request as soon as Anthony called for 0.13 fixes, however this didn't happen yet and I forgot.
On 08/03/2010 04:00 PM, Luiz Capitulino wrote: > On Tue, 03 Aug 2010 09:12:52 +0300 > Avi Kivity<avi@redhat.com> wrote: > >> On 07/07/2010 07:44 PM, Avi Kivity wrote: >>> QEMUFileBuffered stops writing when the underlying QEMUFile is not ready, >>> and tells its producer so. However, when the underlying QEMUFile becomes >>> ready, it neglects to pass that information along, resulting in stoppage >>> of all data until the next tick (a tenths of a second). >>> >>> Usually this doesn't matter, because most QEMUFiles used with QEMUFileBuffered >>> are almost always ready, but in the case of exec: migration this is not true, >>> due to the small pipe buffers used to connect to the target process. The >>> result is very slow migration. >>> >>> Fix by detecting the readiness notification and propagating it. The detection >>> is a little ugly since QEMUFile overloads put_buffer() to send it, but that's >>> the suject for a different patch. >> Ping. > I've queued this fix and another one in a 'for-0.13' branch and was planning > to send a pull request as soon as Anthony called for 0.13 fixes, however > this didn't happen yet and I forgot. Ping again. I don't want to take over Cam's longest-time-to-apply record, so someone apply this please. 0.13 and mainline.
On 07/07/2010 11:44 AM, Avi Kivity wrote: > QEMUFileBuffered stops writing when the underlying QEMUFile is not ready, > and tells its producer so. However, when the underlying QEMUFile becomes > ready, it neglects to pass that information along, resulting in stoppage > of all data until the next tick (a tenths of a second). > > Usually this doesn't matter, because most QEMUFiles used with QEMUFileBuffered > are almost always ready, but in the case of exec: migration this is not true, > due to the small pipe buffers used to connect to the target process. The > result is very slow migration. > > Fix by detecting the readiness notification and propagating it. The detection > is a little ugly since QEMUFile overloads put_buffer() to send it, but that's > the suject for a different patch. > > Signed-off-by: Avi Kivity<avi@redhat.com>\ > Applied. Thanks. Regards, Anthony Liguori > --- > buffered_file.c | 8 ++++++++ > 1 files changed, 8 insertions(+), 0 deletions(-) > > diff --git a/buffered_file.c b/buffered_file.c > index 54dc6c2..a79264f 100644 > --- a/buffered_file.c > +++ b/buffered_file.c > @@ -156,6 +156,14 @@ static int buffered_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, in > offset = size; > } > > + if (pos == 0&& size == 0) { > + DPRINTF("file is ready\n"); > + if (s->bytes_xfer<= s->xfer_limit) { > + DPRINTF("notifying client\n"); > + s->put_ready(s->opaque); > + } > + } > + > return offset; > } > >
On 08/19/2010 06:19 PM, Anthony Liguori wrote: > On 07/07/2010 11:44 AM, Avi Kivity wrote: >> QEMUFileBuffered stops writing when the underlying QEMUFile is not >> ready, >> and tells its producer so. However, when the underlying QEMUFile >> becomes >> ready, it neglects to pass that information along, resulting in stoppage >> of all data until the next tick (a tenths of a second). >> >> Usually this doesn't matter, because most QEMUFiles used with >> QEMUFileBuffered >> are almost always ready, but in the case of exec: migration this is >> not true, >> due to the small pipe buffers used to connect to the target process. >> The >> result is very slow migration. >> >> Fix by detecting the readiness notification and propagating it. The >> detection >> is a little ugly since QEMUFile overloads put_buffer() to send it, >> but that's >> the suject for a different patch. >> >> Signed-off-by: Avi Kivity<avi@redhat.com>\ > > Applied. Thanks. Should be applied to stable-0.13 as well.
diff --git a/buffered_file.c b/buffered_file.c index 54dc6c2..a79264f 100644 --- a/buffered_file.c +++ b/buffered_file.c @@ -156,6 +156,14 @@ static int buffered_put_buffer(void *opaque, const uint8_t *buf, int64_t pos, in offset = size; } + if (pos == 0 && size == 0) { + DPRINTF("file is ready\n"); + if (s->bytes_xfer <= s->xfer_limit) { + DPRINTF("notifying client\n"); + s->put_ready(s->opaque); + } + } + return offset; }
QEMUFileBuffered stops writing when the underlying QEMUFile is not ready, and tells its producer so. However, when the underlying QEMUFile becomes ready, it neglects to pass that information along, resulting in stoppage of all data until the next tick (a tenths of a second). Usually this doesn't matter, because most QEMUFiles used with QEMUFileBuffered are almost always ready, but in the case of exec: migration this is not true, due to the small pipe buffers used to connect to the target process. The result is very slow migration. Fix by detecting the readiness notification and propagating it. The detection is a little ugly since QEMUFile overloads put_buffer() to send it, but that's the suject for a different patch. Signed-off-by: Avi Kivity <avi@redhat.com> --- buffered_file.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-)