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[PATCH v3 00/23] Migration: Transmit and detect zero pages in the multif
[PATCH v3 00/23] Migration: Transmit and detect zero pages in the multifd threads
Wed, 24 Nov 2021 11:05:54 +0100
Trying with a different server.
As it used to happen, when I sent everything only to me, everything worked.
This is a rebase against last master.
And the reason for resend is to configure properly git-publish and
hope this time that git-publish send all the patches.
Since Friday version:
- More cleanups on the code
- Remove repeated calls to qemu_target_page_size()
- Establish normal pages and zero pages
- detect zero pages on the multifd threads
- send zero pages through the multifd channels.
- reviews by Richard addressed.
It pases migration-test, so it should be perfect O:+)
ToDo for next version:
- check the version changes
I need that 6.2 is out to check for 7.0.
This code don't exist at all due to that reason.
- Send measurements of the differences
Friday version that just created a single writev instead of
Right now, multifd does a write() for the header and a writev() for
each group of pages. Simplify it so we send the header as another
member of the IOV.
Once there, I got several simplifications:
* is_zero_range() was used only once, just use its body.
* same with is_zero_page().
* Be consintent and use offset insed the ramblock everywhere.
* Now that we have the offsets of the ramblock, we can drop the iov.
* Now that nothing uses iov's except NOCOMP method, move the iovs
from pages to methods.
* Now we can use iov's with a single field for zlib/zstd.
* send_write() method is the same in all the implementaitons, so use
* Now, we can use a single writev() to write everything.
ToDo: Move zero page detection to the multifd thrteads.
With RAM in the Terabytes size, the detection of the zero page takes
too much time on the main thread.
Last patch on the series removes the detection of zero pages in the
main thread for multifd. In the next series post, I will add how to
detect the zero pages and send them on multifd channels.
Juan Quintela (23):
multifd: Delete useless operation
migration: Never call twice qemu_target_page_size()
multifd: Rename used field to num
multifd: Add missing documention
multifd: The variable is only used inside the loop
multifd: remove used parameter from send_prepare() method
multifd: remove used parameter from send_recv_pages() method
multifd: Fill offset and block for reception
multifd: Make zstd compression method not use iovs
multifd: Make zlib compression method not use iovs
multifd: Move iov from pages to params
multifd: Make zlib use iov's
multifd: Make zstd use iov's
multifd: Remove send_write() method
multifd: Use a single writev on the send side
multifd: Unfold "used" variable by its value
multifd: Use normal pages array on the send side
multifd: Use normal pages array on the recv side
multifd: recv side only needs the RAMBlock host address
multifd: Rename pages_used to normal_pages
multifd: Support for zero pages transmission
multifd: Zero pages transmission
migration: Use multifd before we check for the zero page
migration/multifd.h | 52 +++++++---
migration/migration.c | 7 +-
migration/multifd-zlib.c | 71 +++++--------
migration/multifd-zstd.c | 70 +++++--------
migration/multifd.c | 214 +++++++++++++++++++++++----------------
migration/ram.c | 22 ++--
migration/savevm.c | 5 +-
migration/trace-events | 4 +-
8 files changed, 231 insertions(+), 214 deletions(-)
[PATCH v3 02/23] migration: Never call twice qemu_target_page_size(), Juan Quintela, 2021/11/24
[PATCH v3 03/23] multifd: Rename used field to num, Juan Quintela, 2021/11/24
- [PATCH v3 00/23] Migration: Transmit and detect zero pages in the multifd threads,
Juan Quintela <=