This commit changes lots of stuff in the MS release lifecycle, but
there's no really good way to split this into patches which make sense,
since all the chaos is intensively entangled.
Get rid of the ms_callback complex mess, it is not needed at all.
Previous MS release was strange due to the existance of previous
ms_callback.idle concept and MS storage: the MS signalled when it went
idle (no TBFs attached) and waited for somebody outside to free it,
while then arming itself the release timer to release itself if it was
not released by whoever.
The new lifecycle follows an easier (expected) approach: Whenever all
TBFs become detached from the MS and it becomes idle (use_count becomes
0), then it frees its reserved resources (TFI, etc.) and either:
* frees itself immediatelly under certain conditions (release timeout
configured = 0 or MS garbage with TLLI=GSM_RESERVED_TMSI)
* Arms release_timer and frees itself when it triggers.
If during release_timer the MS is required again (for instance because a
new TBF with TLLI/IMSI of the MS is observed), then a TBF is attached to
the MS and it is considered to become active again, hence the release_timer
is stopped.
OS#6002
Change-Id: Ibe5115bc15bb4d76026918adc1be79469c2f4839
This allows having full information on the control TS easily reachable
(like TRX ofthe PDCH), and makes it easy to compare TS by simply
matching the pointer address.
Change-Id: I6a97b6528b2f9d78dfbca8fb97ab7c621f777fc7
Before this patch, allocate_usf() was implemented to only allocate 1 USF
per TBF, regardless of the available ul_slot mask.
As a result, only 1 slot at max was allocated to any TBF. That's a pity
because usual multislot classes like 12 support up to 2 UL slots per TBF
(in common TS with DL).
This patch reworks allocate_usf() to allocate as many UL multislots as
possible (given mslot class, current USF availability, TFI availability,
related DL TBF slots for the same MS, etc.).
As a result, it can be seen that AllocTest results change substantially
and maximum concurrent TBF allocation drops under some conditions.
That happens due to more USFs being reserved (because each TBF has now
more UL slots reserved). Hence now USF exhaustion becomes the usual
limitation factor as per the number of concurrent TBFs than can be
handled per TRX (as opposed to TFIs previously).
Some of the biggest limitations in test appear though because really
high end multislot classes are used, which can consume high volumes of
UL slots (USFs), and which are probably not the most extended devices in
the field.
Moreover, in general the curren timeslot allocator for a given
multislot class will in general try to optimize the DL side gathering
most of the possible timeslots there. That means, for instance on ms
class 12 (4 Tx, 4Rx, 5 Sum), 4 DL slots and 1 UL slot will still be
selected. But in the case where only 3 PDCHs are available, then with
this new multi-slot UL support a TBF will reserve 3 DL slots and 2 UL
slots, while before this patch it would only taken 1 UL slot instead of
2.
This USF exhaustion situation can be improved in the future by
parametrizing (VTY command?) the maximum amount of UL slots that a TBF
can reserve, making for instance a default value of 2, meaning usual
classes can gather up 2 UL timelosts at a time while forbidding high-end
hungry classes to gather up to 8 UL timeslots.
Another approach would be to dynamically limit the amount of allowed
reservable UL timeslots based on current USF reservation load.
Related: OS#2282
Change-Id: Id97cc6e3b769511b591b1694549e0dac55227c43
The table B.1 is copy-pasted from 3GPP TS 45.002 and reformatted via
Emacs macros into C struct to avoid typos. The test output expanded
accordingly.
The allocation test expectations and output are adjusted accordingly.
Note: classes 35-45 which need TA offset are not properly supported
yet. This can be extended once we have such devices available for tests.
Change-Id: I1ef2eb99c517f25e7d1e71b985a3e0eb3879eb2c
Related: OS#2282
So far the allocation was only tested up to hardcoded MS class 29. Drop
that assumption and test for all supported MS classes. Adjust expected
test output as necessary.
Note: using mslot_class_max() forces allocation for MS classes 30 and 31
for which no actual data is available (will be added in follow-up
patches) which current implementation treats differently depending on
TX/RX direction - see gprs_alloc_max_dl_slots_per_ms(). Because of that
we have to adjust the expected number of allocations in
test_successive_allocation() as well.
Change-Id: I7737f303d97197ef159b14a19c3312a11f07b433
Related: OS#2282
* print MS classes
* unify and print test mode description
* print additional info on test completion
This only changes meta info about test run but not the actual test
output.
Change-Id: I30a4b8f561a9677f4e9ded33a051a249bd15a6a2
Related: OS#2282
This patch adds a test case test_2_consecutive_dl_tbfs which
expects a current bug with TS allocation for 2nd DL TBF.
The test's expectation is corrected along with the bug fix in a
subsequent commit
Related: OS#1792
Change-Id: I890e4fbb2b64037e051433e70082a197e2a929a6
Currently there is no persistent state being used in
alloc_algorithm_dynamic. So algorithm B is even used in persistent
high usage scenarios. If there are many active TBFs, multislot
assigments are not fair, because MS of a "higher" multislot class get
higher troughputs. On the other hand, as long as all PDCH are busy no
bandwidth will be wasted even if all MS use algorithm A.
This commit modifies alloc_algorithm_dynamic to disable algorithm B
when that call fails. It then keeps it disabled until there is a
single PDCH which is idle (it is considered idle, if there is at most
one active DL TBF assigned to it).
Sponsored-by: On-Waves ehf
Currently algorithm A can select an TBF even when there is no free
TBF in the reverse direction. While this does not necessarily lead to
an allocation failure, the probabily is higher. In addition, the
current slot reservations are not taken into account.
This commit changes the selection algorithm to prefer slots where TFI
are available in both directions and which are less reserved.
Sponsored-by: On-Waves ehf
The idea behind this meta algorithm is to automatically select one of
the other algorithms based on the system state. Basically algorithm B
will be selected if the PDCH usage is low to improve throughput and
latency. Algorithm A will be selected to support more concurrent MS.
This commit adds a first simple state-less version of this algorithm
that always tries B first and only if that fails A is tried
afterwards.
The following VTY command is added to the 'pcu' node:
- alloc-algorithm dynamic
Ticket: #1934
Sponsored-by: On-Waves ehf
MS iniated TCP connections generally result in a sequence
of short time UL and longer lasting DL TBFs, being interleaved
between several MS. This scenario is not covered by the existing
tests.
This commit adds a test, that allocates as man as possible TBFs
several times with different test modes without clearing the BTS (and
thus the TBF list) in between. The number of allocated DL TBFs in
each round is expected to be constant.
Sponsored-by: On-Waves ehf
Currently the TFI are managed per TRX, thus only a maximum of 32 TBF
per direction and per TRX are possible simultaneously.
This commit modifies algorithm_a() to allow the sharing of TFI
between different PDCH. Since algorithm A only assigns a single slot
to each TBF, the TFI of each PDCH can be assigned independently.
This increases the maximum to 32 TBF per direction and per PDCH
concerning the TFI allocation.
Ticket: #1793
Sponsored-by: On-Waves ehf
Currently the handling of MS_B and MS_C is not compliant with TS
45.002, annex B.1. These values may only interpreted as 0, if
frequency hopping is not enabled and if there is no change from Rx to
Tx or vice-versa.
This commit sets Ttb/Trb to 1 if the table entry is MS_B/MS_C, since
only combined down/up access modes are supported.
Sponsored-by: On-Waves ehf
Currently the masks are computed equally for each class type. This
does not make much sense for class type 2 MS, since those are capable
to work in full duplex mode.
This commit sets the masks to 0xff for class type 2 MS.
Sponsored-by: On-Waves ehf
According to TS 45.002, 6.4.2.2 the choice whether Tta or Tra has to
be applied, depends on the medium access mode (currently always
dynamic) and the number of UL/DL slots. Currently either value can be
used which might result in combinations not covered by the spec.
This commit changes find_multi_slots() to skip non-compliant
combinations.
Note that this code will have to be extended, if other medium
access modes are implemented.
Sponsored-by: On-Waves ehf
Currently the slot selection of algorithm A is based on the current
slot usage by active TBF. Especially in the Dl after UL case which
reflects the commen use case "MS initiates TCP connection", the
resulting distribution is not optimal with respect to PDCH usage.
This commit changes the implementation to use the slot reservation
information instead.
Sponsored-by: On-Waves ehf
Currently when using the test modes TEST_MODE_DL_AFTER_UL or
TEST_MODE_UL_AFTER_DL, the first TBF is deleted before the second is
allocated. The far more interesting case were to keep the first TBF a
little bit longer until the second TBF has been created and delete
then. This comes closer the the situation observed with real MS,
where the first TBF takes some time (timeout or waiting for Ack)
before it gets deleted and thus detached from the MS object.
This commit delays the call to tbf_free accordingly.
The effect can be observed in the results of the algo A tests, where
the uniform distribution of the allocated PDCH is lost.
Sponsored-by: On-Waves ehf
Currently the search of the "best" slot combination is done
separately from the UL slot selection, which can lead to an
allocation failure due to USF exhaustion even if another combination
had been possible.
This commit reduces the probability for this event by skipping UL
slots without free USF while calculation the capacity.
Note that the implementation is rather inefficient which will be
fixed by the following commits.
Sponsored-by: On-Waves ehf
Since currently the algorithm B will only allocate a single UL slot
and will have to stick to it (first common TS), the other possible UL
slots will not be allocated while the reservation is kept.
This commit adds code to update the reserved set of UL slots to only
reserve the single common TS when the UL TBF is allocated.
Interestingly this leads to fewer allocated TBF in some cases due to
USF exhaustion. This will be improved by the following commit "alloc:
Skip common TS without free USF".
Sponsored-by: On-Waves ehf
Currently al possible UL slots are included in the capacity
calculation which is the base of the slot selection. Nevertheless
UL-only slots will never be used, since only one uplink slot (which
must be a common slot) will be used.
This patch changes the code to only include common slots in the
capacity sum.
Note that this might not be optimal if algorithm B supported
multiple uplink slots.
Sponsored-by: On-Waves ehf
The current implementation always starts the downlink slot allocation
with the first possible slot, depending on which channels are enabled
and which multislot class is offered by the MS. So in configurations
with many (>4) PDCH, some PDCH are not really used.
The new implementation introduced by this commit differs as follows:
- The reservation mechanism provided by GprsMs is used to avoid
incompatibilities is used in the same way like algo A does. This
basically means, that the allocation is done once when the first
TBF is requested and then used until all TBF have been released.
- All combinations of Rx and Tx slots are checked for compatibility
with the multiscot class. Basically the combination with the most
usable PDCH and the least number of reservations is used.
- Only one UL slots is provided.
- Tta and Tra are checked.
Sponsored-by: On-Waves ehf
Currently only the first enabled PDCH will be used. Beside the
throughput this will also limit the number of TBFs:
- number of UL TBFs <= 7
- number of DL TBFs <= 32
This commit changes the allocation algorithm to use the PDCH with the
least number of attached TBFs. This will improve the troughput in
both directions and the UL limits:
- number of UL TBFs <= min(32, N_PDCH * 7) UL TBFs
Ticket: #1794
Sponsored-by: On-Waves ehf
This commit adds:
- an assertion to check that count is valid,
- an assertion the verify that tbf_alloc did not fail
- a slots parameter to specify the enabled slots
- additional test invocations with more slots enabled
Sponsored-by: On-Waves ehf
This test allocates as many as possible UL/DL TBF pairs, shows their
PDCH usage, and checks how many of them has been created
successfully.
Sponsored-by: On-Waves ehf
The allocation in the TBF/BTS code is quite complex. In parts this
is due the assignment and requests occuring under differen circumstances.
Attempt to re-create the commono scenarios.
Remove the bogus msclass check in gprs_rlcmac_tbf::update as the
allocation code will check the ms class anyway.
Pau Espin
Pau Espin Pedrol