[PATCH 1/2] docs: Clarify 'burst' units for QoS
The burst attribute for bandwidth specifies how much bytes can be
transmitted in a single burst. Therefore, the unit is in
multiples of 1024 (thus kibibytes) not SI-like 1000. It always
has been like that.
The 'tc' output is still confusing though, for instance:
# tc class add dev $DEV parent 1: classid 1:1 htb rate 1000kbps burst 2097152
# tc class show dev vnet2
class htb 1:1 root rate 8Mbit ceil 8Mbit burst 2Mb cburst 1600b
Please note that 2097152 = 2*1024*1024. Even the man page is
confusing. From tc(8):
kb or k Kilobytes
mb or m Megabytes
But I guess this is because 'tc' predates IEC standardisation of
binary multiples and thus can't change without breaking scripts
parsing its output.
And while at it, adjust _virNetDevBandwidthRate struct member
description, to make it obvious which members use SI/IEC units.
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
docs/formatnetwork.html.in | 2 +-
src/util/virnetdevbandwidth.h | 8 ++++----
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/docs/formatnetwork.html.in b/docs/formatnetwork.html.in
index b1b2391f43..fad43f77ea 100644
--- a/docs/formatnetwork.html.in
+++ b/docs/formatnetwork.html.in
@@ -634,7 +634,7 @@
</dd>
<dt><code>burst</code></dt>
<dd>
- Optional attribute which specifies the amount of kilobytes that
+ Optional attribute which specifies the amount of kibibytes that
can be transmitted in a single burst at <code>peak</code> speed.
</dd>
<dt><code>floor</code></dt>
diff --git a/src/util/virnetdevbandwidth.h b/src/util/virnetdevbandwidth.h
index 3d520721f6..c82029fc0f 100644
--- a/src/util/virnetdevbandwidth.h
+++ b/src/util/virnetdevbandwidth.h
@@ -23,10 +23,10 @@
typedef struct _virNetDevBandwidthRate virNetDevBandwidthRate;
struct _virNetDevBandwidthRate {
- unsigned long long average; /* kbytes/s */
- unsigned long long peak; /* kbytes/s */
- unsigned long long floor; /* kbytes/s */
- unsigned long long burst; /* kbytes */
+ unsigned long long average; /* kilobytes/s */
+ unsigned long long peak; /* kilobytes/s */
+ unsigned long long floor; /* kilobytes/s */
+ unsigned long long burst; /* kibibytes */
};
typedef struct _virNetDevBandwidth virNetDevBandwidth;
--
2.34.1