| Message ID | 20180724121753.5753-4-lbloch@janustech.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduction of l2-cache-full option for qcow2 images | expand |
On 07/24/2018 07:17 AM, Leonid Bloch wrote: > Signed-off-by: Leonid Bloch <lbloch@janustech.com> > --- > docs/qcow2-cache.txt | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/docs/qcow2-cache.txt b/docs/qcow2-cache.txt > index a0a1267482..43c0faaddb 100644 > --- a/docs/qcow2-cache.txt > +++ b/docs/qcow2-cache.txt > @@ -110,11 +110,12 @@ How to configure the cache sizes > Cache sizes can be configured using the -drive option in the > command-line, or the 'blockdev-add' QMP command. > > -There are three options available, and all of them take bytes: > +There are four options available: > > -"l2-cache-size": maximum size of the L2 table cache > -"refcount-cache-size": maximum size of the refcount block cache > -"cache-size": maximum size of both caches combined > +"l2-cache-size": maximum size of the L2 table cache (bytes, K, M) > +"refcount-cache-size": maximum size of the refcount block cache (bytes, K, M) > +"cache-size": maximum size of both caches combined (bytes, K, M) > +"l2-cache-full": make the L2 cache cover the full image (boolean) > > There are a few things that need to be taken into account: > Worth mentioning that the first three can be combined (although usually you'll never specify more than 2; as specifying all 3 requires that you perform the correct addition), but that the third is mutually exclusive? > @@ -130,6 +131,9 @@ There are a few things that need to be taken into account: > memory as possible to the L2 cache before increasing the refcount > cache size. > > +- If "l2-cache-full" is specified, QEMU will assign enough memory > + to the L2 cache to cover the entire size of the image. > + > Unlike L2 tables, refcount blocks are not used during normal I/O but > only during allocations and internal snapshots. In most cases they are > accessed sequentially (even during random guest I/O) so increasing the >
On 07/24/2018 06:21 PM, Eric Blake wrote:
On 07/24/2018 07:17 AM, Leonid Bloch wrote:
Signed-off-by: Leonid Bloch [1]<lbloch@janustech.com>
---
docs/qcow2-cache.txt | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/docs/qcow2-cache.txt b/docs/qcow2-cache.txt
index a0a1267482..43c0faaddb 100644
--- a/docs/qcow2-cache.txt
+++ b/docs/qcow2-cache.txt
@@ -110,11 +110,12 @@ How to configure the cache sizes
Cache sizes can be configured using the -drive option in the
command-line, or the 'blockdev-add' QMP command.
-There are three options available, and all of them take bytes:
+There are four options available:
-"l2-cache-size": maximum size of the L2 table cache
-"refcount-cache-size": maximum size of the refcount block cache
-"cache-size": maximum size of both caches combined
+"l2-cache-size": maximum size of the L2 table cache (bytes,
K, M)
+"refcount-cache-size": maximum size of the refcount block cache
(bytes, K, M)
+"cache-size": maximum size of both caches combined
(bytes, K, M)
+"l2-cache-full": make the L2 cache cover the full image
(boolean)
There are a few things that need to be taken into account:
Worth mentioning that the first three can be combined (although
usually you'll never specify more than 2; as specifying all 3
requires that you perform the correct addition), but that the third
is mutually exclusive?
Actually, only 2 of the first 3 can be specified. But you're right, I
need to write about mutual exclusivity in the docs. Will fix in v2.
Thanks!
@@ -130,6 +131,9 @@ There are a few things that need to be taken
into account:
memory as possible to the L2 cache before increasing the
refcount
cache size.
+- If "l2-cache-full" is specified, QEMU will assign enough memory
+ to the L2 cache to cover the entire size of the image.
+
Unlike L2 tables, refcount blocks are not used during normal I/O
but
only during allocations and internal snapshots. In most cases they
are
accessed sequentially (even during random guest I/O) so increasing
the
References
1. mailto:lbloch@janustech.com
diff --git a/docs/qcow2-cache.txt b/docs/qcow2-cache.txt index a0a1267482..43c0faaddb 100644 --- a/docs/qcow2-cache.txt +++ b/docs/qcow2-cache.txt @@ -110,11 +110,12 @@ How to configure the cache sizes Cache sizes can be configured using the -drive option in the command-line, or the 'blockdev-add' QMP command. -There are three options available, and all of them take bytes: +There are four options available: -"l2-cache-size": maximum size of the L2 table cache -"refcount-cache-size": maximum size of the refcount block cache -"cache-size": maximum size of both caches combined +"l2-cache-size": maximum size of the L2 table cache (bytes, K, M) +"refcount-cache-size": maximum size of the refcount block cache (bytes, K, M) +"cache-size": maximum size of both caches combined (bytes, K, M) +"l2-cache-full": make the L2 cache cover the full image (boolean) There are a few things that need to be taken into account: @@ -130,6 +131,9 @@ There are a few things that need to be taken into account: memory as possible to the L2 cache before increasing the refcount cache size. +- If "l2-cache-full" is specified, QEMU will assign enough memory + to the L2 cache to cover the entire size of the image. + Unlike L2 tables, refcount blocks are not used during normal I/O but only during allocations and internal snapshots. In most cases they are accessed sequentially (even during random guest I/O) so increasing the
Signed-off-by: Leonid Bloch <lbloch@janustech.com> --- docs/qcow2-cache.txt | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)