Re: [Qemu-devel] [PATCH 2/4] docs: Fix an inaccuracy due to recent changes

[Leonid Bloch]

   On 07/24/2018 06:20 PM, Eric Blake wrote:

     On 07/24/2018 07:17 AM, Leonid Bloch wrote:

     Signed-off-by: Leonid Bloch [1]<address@hidden>
     ---
       docs/qcow2-cache.txt | 6 +++---
       1 file changed, 3 insertions(+), 3 deletions(-)
     diff --git a/docs/qcow2-cache.txt b/docs/qcow2-cache.txt
     index 8a09a5cc5f..a0a1267482 100644
     --- a/docs/qcow2-cache.txt
     +++ b/docs/qcow2-cache.txt
     @@ -97,9 +97,9 @@ need:
          l2_cache_size = disk_size_GB * 131072
          refcount_cache_size = disk_size_GB * 32768
       -QEMU has a default L2 cache of 1MB (1048576 bytes) and a refcount
     -cache of 256KB (262144 bytes), so using the formulas we've just
     seen
     -we have
     +QEMU has a default L2 cache of 1MB (1048576 bytes) or 8 clusters
     (whichever
     +is larger) and a refcount cache of 256KB (262144 bytes), so using
     the

     Looks suspicious; isn't the refcount cache size also dependent on
     the cluster size?

   Yes, it's 4*cluster_size. But I realize now that the text here speaks
   about the default sizes, which means with with 64KB clusters. So this
   fix is not necessary. Will drop this patch.

     +formulas we've just seen we have (assuming the L2 cache is 1MB):
            1048576 / 131072 = 8 GB of virtual disk covered by that cache
           262144 /  32768 = 8 GB

References

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