Meta's resource control demo project[0] includes a benchmark tool that can
be used to calculate the best iocost solutions for a given SSD.
[0]: https://github.com/facebookexperimental/resctl-demo
A project[1] has now been started to create a publicly available database
of results that can be used to apply them automatically.
[1]: https://github.com/iocost-benchmark/iocost-benchmarks
This change adds a new tool that gets triggered by a udev rule for any
block device and queries the hwdb for known solutions. The format for
the hwdb file that is currently generated by the github action looks like
this:
# This file was auto-generated on Tue, 23 Aug 2022 13:03:57 +0000.
# From the following commit:
# ca82acfe93
#
# Match key format:
# block:<devpath>:name:<model name>:
# 12 points, MOF=[1.346,1.346], aMOF=[1.249,1.249]
block:*:name:HFS256GD9TNG-62A0A:fwver:*:
IOCOST_SOLUTIONS=isolation isolated-bandwidth bandwidth naive
IOCOST_MODEL_ISOLATION=rbps=1091439492 rseqiops=52286 rrandiops=63784 wbps=192329466 wseqiops=12309 wrandiops=16119
IOCOST_QOS_ISOLATION=rpct=0.00 rlat=8807 wpct=0.00 wlat=59023 min=100.00 max=100.00
IOCOST_MODEL_ISOLATED_BANDWIDTH=rbps=1091439492 rseqiops=52286 rrandiops=63784 wbps=192329466 wseqiops=12309 wrandiops=16119
IOCOST_QOS_ISOLATED_BANDWIDTH=rpct=0.00 rlat=8807 wpct=0.00 wlat=59023 min=100.00 max=100.00
IOCOST_MODEL_BANDWIDTH=rbps=1091439492 rseqiops=52286 rrandiops=63784 wbps=192329466 wseqiops=12309 wrandiops=16119
IOCOST_QOS_BANDWIDTH=rpct=0.00 rlat=8807 wpct=0.00 wlat=59023 min=100.00 max=100.00
IOCOST_MODEL_NAIVE=rbps=1091439492 rseqiops=52286 rrandiops=63784 wbps=192329466 wseqiops=12309 wrandiops=16119
IOCOST_QOS_NAIVE=rpct=99.00 rlat=8807 wpct=99.00 wlat=59023 min=75.00 max=100.00
The IOCOST_SOLUTIONS key lists the solutions available for that device
in the preferred order for higher isolation, which is a reasonable
default for most client systems. This can be overriden to choose better
defaults for custom use cases, like the various data center workloads.
The tool can also be used to query the known solutions for a specific
device or to apply a non-default solution (say, isolation or bandwidth).
Co-authored-by: Santosh Mahto <santosh.mahto@collabora.com>
In 5118e8e71d, the rules were changed to add
OPTIONS="string_escape=replace" to creation of
ENV{ID_SERIAL}="$env{ID_MODEL}_$env{ID_SERIAL_SHORT}", so that "/" would be
escaped. But this also changes how the symlink looks for devices that do not
have "/". This adds back the old symlink for compat, except when a slash
is present.
In the meantime, we changed the symlink format to include ${ND_NSID}. Since
the symlink with unescaped characters are older than that, for compat we
only need to cover the older type. (Symlinks without escaping and with ${ND_NSID}
were never created.) This makes it slightly easier on users: the non-deprecated
symlinks are with "_${ND_NSID}", so they are easier to distinguish.
Fixes#27155.
Mostly untested :( I only have a boring nvme device with no special characters
in the id, and the symlinks are unchanged for it by this patch.
The nvme by-id symlink changes to the latest namespace when a new namespace gets
added, for example by connecting multiple NVMe/TCP host controllers via nvme
connect-all.
That is incorrect for persistent device links.
The persistent symbolic device link should continue to point to the same NVMe
namespace throughout the lifetime of the current boot.
Therefore the namespace id needs to be added to the link name.
This adds symlinks that allow accessing loopback block devices via stable
names that reference their backing block devices, make the unpredictable
naming of loopback devices less of an issue.
Example:
1. Create a loopback block device for a file $F
losetup --find $F
2. Reference the backing block device via its inode:
L="$(stat -c '/dev/loop/by-inode/%Hd:%Ld-%i' $F)"
fdisk $L
In the above the loop device name (which might be /dev/loop47 or any
other name) is not used at all.
When built without blkid, then udev-builtin-blkid is not built,
and the verifier warns about the unknown builtin:
60-persistent-storage.rules:114 Unknown builtin command: blkid --hint=session_offset=$env{ID_CDROM_MEDIA_SESSION_LAST_OFFSET}
60-persistent-storage.rules:117 Unknown builtin command: blkid --noraid
60-persistent-storage.rules:120 Unknown builtin command: blkid
60-persistent-storage.rules: udev rules check failed
We would execute up to four hwdb match patterns (+ the keyboard builtin):
After the first hit, we would skip the other patterns, because of the GOTO="evdev_end"
action.
57bb707d48 (rules: Add extended evdev/input match
rules for event nodes with the same name), added an additional match with
":phys:<phys>:ev:<ev>" inserted. This breaks backwards compatibility for user
hwdb patterns, because we quit after the first match.
In general hwdb properties are "additive". We often have a general rule that
matches a wider class and then some specific overrides. E.g. in this particular
case, we have a match for all trackpoints, and then a bunch of model-specific
settings.
So let's change the rules to try all the match patterns and combine the
received properties. We execute builtin-keyboard once at the end, if there was
at least one match.
Fixes#25698. Fixes https://bugzilla.redhat.com/show_bug.cgi?id=2152226.
This also impacts other cases which I think would be very confusing for users.
Since we quit after a first successful match, if we had e.g. a match for
'evdev:input:b*v*p*' in out database, and the user added a match using
'evdev:name:*', which is the approach we document in the .hwdb files and which
users quite often use, it would be silently ignored. What's worse, if we added
our 'evdev:input:b*v*p*' match at a later point, user's match would stop
working. If we combine all the properties, we get more stable behaviour.
After 479da1107a, the usb_id builtin
command does not set ID_SERIAL if ID_BUS is already set.
Before the commit, all properties set based on pci bus were overwritten
by the usb_id, hence now it is sufficient setting them only when ID_BUS is
not set yet.
Fixes#25238.
Previously, ata_id might not be able to retrieve attributes correctly,
and properties from usb_id were used as a fallback. See issue #24921
and PR #24923. To keep backward compatibility, still we need to create
symlinks based on USB serial.
Fixes#25179.
If no module name is provided, then try to load modules based on the
device modealias.
Previously, MODALIAS property is passed as an argument, but it may
contain quotation. Hence, unfortunately the modalias may be modified
and cannot load expected modules.
Fixes#24715.
The uverbs devices are sequentially numbered and are not guarranteed to
stay stable across reboot.
At least one good person was disappointed by this, because they couldn't
find their device: https://bugzilla.redhat.com/show_bug.cgi?id=2036515
Let's add a few helpful links.
