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2015-07-16alloc: Fix MS_B/MS_C interpretationJacob Erlbeck1-4/+12
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
2015-07-16alloc: Do not use masking for multislot class type 2 MSJacob Erlbeck1-4/+12
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
2015-07-16alloc: Select applicable Tta/TraJacob Erlbeck1-9/+44
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
2015-07-16alloc: Use an enum instead of numbers to select the maskJacob Erlbeck1-10/+12
The local enums MASK_TT and MASK_TR replace the hard coded indices. The variable m_idx is renamed to mask_sel for more clarity. Sponsored-by: On-Waves ehf
2015-07-16alloc: Merge find_least_busy_pdch and find_least_reserved_pdchJacob Erlbeck1-59/+19
Both functions only differ in the computation of the value for num_tbfs. This commit merge both functions and adds a parameter containing a function for that compuation. Sponsored-by: On-Waves ehf
2015-07-15sba: Fix loop exit in SBAController::alloc (Coverity)Jacob Erlbeck1-1/+1
The commit 506f156f7a4aebb52dace00a760f86b2b4f5e19a has reverted the TS search order. The outer loop exit condition was not updated accordingly. This bug would would only lead to an error if there were multiple TRX where the first TRX has not got any PDCH assigned. This commit corrects the break condition. Fixes: Coverity CID 1311776 Sponsored-by: On-Waves ehf
2015-07-14llc: Fix comparison warningJacob Erlbeck1-1/+1
Fixes: Jenkins build #609 warning Addresses: llc.cpp:56, GNU C Compiler 3 (gcc), Priority: Normal comparison between signed and unsigned integer expressions Sponsored-by: On-Waves ehf
2015-07-07alloc: Use least reserved PDCH for algo AJacob Erlbeck1-1/+60
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
2015-07-07sba: Reverse TS search orderJacob Erlbeck1-2/+2
Currently the search for an enabled PDCH slot for SBA start with the first TS. If there are more than 2 PDCH slots enabled, this slot will conflict with an existing multislot reservation for most multislot classes. This were less likely if the search were reversed and started with the last slot due to the 3 slot shift between Tx and Rx. When multislot allocation is enabled and several MS are connected, and increased rate of poll timeouts can be observed. This commit tries to reduce the number of poll timeouts by reverting the slot search order for SBA allocation. Sponsored-by: On-Waves ehf
2015-07-07alloc: Disable inner loop debugging by defaultJacob Erlbeck1-9/+15
The current logging statements within the inner loop of find_multi_slots drain quite a lot of CPU resources even if LOGL_DEBUG is not enabled. This might cause issues on the target hardware. This commit disables these LOGP calls unless the ENABLE_TS_ALLOC_DEBUG macro has been set explicitly. This results in a reduction in the CPU usage reported by callgrind for find_multi_slots from 42% to 25% when executing AllocTest. Sponsored-by: On-Waves ehf
2015-07-07alloc: Optimize find_free_usfJacob Erlbeck1-9/+4
According to callgrind, this function consumes 33% CPU when running the AllocTest program. This commit uses the assigned_usf() method to get the USFs allocated by a PDCH instead of traversing the TBFs. Sponsored-by: On-Waves ehf
2015-07-07tbf: Keep a set of used TFI and USF per PDCHJacob Erlbeck2-4/+39
Currently is is rather expensive to get TFI and USF usage per PDCH, because the TBFs need to be scanned to get that information. This commit adds corresponding bit sets which get updated by the attach_tbf/detach_tbf methods of the gprs_rlcmac_pdch class. Sponsored-by: On-Waves ehf
2015-07-07alloc: Skip common TS without free USF when ratingJacob Erlbeck1-3/+5
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
2015-07-07alloc: Only reserve 1 UL slot with algorithm BJacob Erlbeck1-0/+5
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
2015-07-07alloc: Set minimum slot capacity to 1Jacob Erlbeck1-0/+2
Currently the capacity of a PDCH slot is calculated as 32 - N_reserved for each direction. This can result in a capacity of 0 and even negative values. This commit forces the capacity of an usable slot to be at least zero under the assumption, that an overly reserved PDCH is still better than none. Sponsored-by: On-Waves ehf
2015-07-07alloc: Only use common UL slots when calculating the capacityJacob Erlbeck1-1/+2
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
2015-07-07alloc: Replace Algorithm B implementationJacob Erlbeck1-418/+374
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
2015-07-07tbf: Add Poll Timeout countersJacob Erlbeck3-0/+20
This commits adds three poll timeout counters - RLC Assign Timeout - RLC Ack Timeout - RLC Release Timeout to help diagnosing to cause for these events. There seems to be an increased rate of these when a PDCH is shared by multiple TBFs. Sponsored-by: On-Waves ehf
2015-07-03Revert "tbf: Add GprsMs* argument to update() and use it in reuse_tbf"Jacob Erlbeck2-10/+4
This reverts commit 2272a83a13b57ea7e99fe96ac76e4ad892e19e90. The modification is no longer needed, since the call to update has been removed from reuse_tbf(). Conflicts: src/tbf_dl.cpp Sponsored-by: On-Waves ehf
2015-07-03tbf: Remove call to update() in reuse_tbfJacob Erlbeck1-2/+0
Since both TBF are based on the same reservation which means that they should be compatible with respect to the slot usage, and since the new TBF has not been forced to single slot usage, an update of the allocation is not necessary now. This commit removes the call to update() from within reuse_tbf(). Sponsored-by: On-Waves ehf
2015-07-03tbf: Set ms in call to tbf_alloc_dl_tbfJacob Erlbeck1-3/+1
The call to tbf_alloc_dl_tbf misses the pointer to the GprsMs object which is already known in that case (tbf_reuse). This leads to a full reallocation of the PDCH slots, which is possibly incompatible with the old set of slots. This can result in hanging TCP connections and TCP connection failures. This commit replaces the old NULL value by the actual GprsMs object. Since the set_ms() is also done within the tbf_alloc_dl_tbf method, that call is removed. Sponsored-by: On-Waves ehf
2015-07-03alloc: Base algo A on reserved PDCHsJacob Erlbeck1-9/+11
Currently algorithm A bases its time slots selection on the number of TBF actively using the PDCHs. This statistically prefers the first time slots, especially with short living TBFs. So when the first TBF is triggered by an uplink transfer (which generally results in a short-lived TBF) the potentially longer living DL TBF will be bound to the same slot. When another MS then requests an uplink TBF, it will get the same slot (no UL TBF currently active). This commit changes the algorithm to base its selection on reserved slots instead. Sponsored-by: On-Waves ehf
2015-07-03alloc: Ignore slots with differing TSC if multiple slots are requestedJacob Erlbeck1-1/+18
According to TS 45.002, 6.4.2 the training sequence (TSC) must be the same for all slots in a multi-slot set. This commit updates find_possible_pdchs() to only consider slots with the same TSC if more that 1 slot shall be assigned. Note that the first PDCH's TSC will be used as reference, so if two or more groups with a common TSC are configured, only the first will be used. This restriction does not apply to algorithm A, since it will not assign more than one slot and therefore sets the max_slots parameter to 1. Sponsored-by: On-Waves ehf
2015-07-03ms: Get the set of slots currently activeJacob Erlbeck4-0/+66
This commits adds methods to GprsMs and gprs_rlcmac_tbf to retrieve the slots that are actively used. Sponsored-by: On-Waves ehf
2015-07-03ms: Add support for slot reservationJacob Erlbeck4-3/+102
In contrast to the slots currently used by existing TBFs, the reserved slots refer to the time slots that can be used for newly allocated TBFs without causing conflicts (given that the first common TS does not change). They correspond to the potential use of the PDCHs and can be used to achieve a more uniform slot allocation. This commit adds bit set based methods to GprsMs and gprs_rlcmac_trx and a counter to gprs_rlcmac_pdch. The current TRX will also be stored in the MS object. Sponsored-by: On-Waves ehf
2015-07-03alloc: Load balancing for algo AJacob Erlbeck1-13/+107
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
2015-07-03tbf: Add GprsMs* argument to update() and use it in reuse_tbfJacob Erlbeck3-5/+11
Since set_ms() is caled on the new DL TBF, the old DL TBF loses the reference to the MS object. This will lead to a segfault, when update() is called in reuse_tbf(). This commit adds an optional GprsMs* parameter to update() and uses it for the slot allocation. This fixes a TbfTest crash that would otherwise occur after applying the next commit. Sponsored-by: On-Waves ehf
2015-07-03ms: Add tbf() method to get the TBF based on the directionJacob Erlbeck3-0/+16
To avoid the need for a switch or conditional statement when needing a TBF from an MS object in direction independant code, this method contains that case distinction. For additional flexibility, a reverse() function is added to get the opposite direction. Sponsored-by: On-Waves ehf
2015-07-03ms: Add first_common_ts method to GprsMsJacob Erlbeck2-0/+13
This method gets the index (0 based) of first common time slot used by the TBFs attach to it. It expects that all of them have the same notion of this. If no TBF is attached, -1 will be returned. Sponsored-by: On-Waves ehf
2015-07-03tbf: Maintain the number of TBF per PDCHJacob Erlbeck4-8/+49
Currently the PDCH object do not know anything about the TBFs using them. To make the slot allocation load dependant, at least some numbers are required. This commit adds TBF counters (one per direction) and the related methods attach_tbf, detach_tbf, and num_tbfs to gprs_rlcmac_pdch. Sponsored-by: On-Waves ehf
2015-06-29tbf: Add BTS::ms_alloc methodJacob Erlbeck5-14/+30
Currently the code that creates the MS objects with tbf.cpp is duplicated. This commit moves the corresponding code into a new method. Since there is no TLLI available there, the GprsMsStorage::create_ms method has been refactored into two variants: one with TLLI/direction and one without. Sponsored-by: On-Waves ehf
2015-06-29tbf: Always create an MS object on TBF allocationJacob Erlbeck3-31/+32
Currently the MS object are created when the TLLI gets known. Therefore some information (TA, MS class) must be stored in the TBF itself and is copied to the MS object later on. This would get even more complex, if the allocation algorithms were extended based on this scheme. This commit ensures, that an MS object will always be created on TBF allocation, even if the TLLI is not yet known. These 'anonymous' objects are still managed by the MS storage. To avoid dangling entries without a TLLI there (which cannnot be retrieved anyway), the timer in the MS objects is not started after all TBF have been detached, so that they get deleted immediately in that case. Note that an MS object can still be removed (e.g. by replacement) from an existing TBF, so tbf->ms() can be NULL. Ticket: #1794 Sponsored-by: On-Waves ehf
2015-06-29tbf: Pass the MS object around instead of old_tbfJacob Erlbeck7-33/+36
Currently the old TBF (either uplink or downlink) is passed around at TBF allocation mainly to get information about the MS. To implement more complex allocation algorithms, the MS object itself will be needed anyway. This commit replaces the old_tbf arguments by MS object arguments. Sponsored-by: On-Waves ehf
2015-06-29tbf: Remove update_tlli methodJacob Erlbeck3-7/+0
This method does not do anything anymore, it's functionality has been taken over by update_ms. This commit removes gprs_rlcmac_tbf::update_tlli completely. Sponsored-by: On-Waves ehf
2015-06-29vty: Fix documentation for 'no cs downgrade-threshold'Jacob Erlbeck1-1/+1
The NO_STR is missing, this commit adds it. Fixes: Jenkins #603 Sponsored-by: On-Waves ehf
2015-06-29llc: Add missing include directive for struct timevalJacob Erlbeck1-1/+1
While including time.h is sufficient with Ubuntu's current libc6 2.19, the correct (and portable) include file is sys/time.h. This commit modifies the include directive in llc.h accordingly. Fixes: Jenkins #600 Addresses: In file included from gprs_ms.h:28, from gprs_ms.cpp:22: llc.h:68: error: field 'recv_time' has incomplete type llc.h:69: error: field 'expire_time' has incomplete type Sponsored-by: On-Waves ehf
2015-06-22llc: Move storage of timestamps into gprs_llc_queueJacob Erlbeck3-25/+38
Currently the receive and expiry timestamps are prepended to the LLC msgb before it is passed to gprs_llc_queue::enqueue(). Since this meta information should not be counted as LLC octets, the gprs_llc_queue needs to known about this (unless the correction was done in the LLC layer). This commit moves the meta information storage code into gprs_llc_queue. The meta data is now stored in the control block (cb) area of the msgb. Note that the info pointer that is returned from the dequeue method is only valid if that method returns a (non-NULL) msgb. It must not be used after that msgb has been modified or freed. Sponsored-by: On-Waves ehf
2015-06-22llc: Make timeval arguments constJacob Erlbeck4-7/+10
Some struct timeval pointer arguments do not have the const qualifier, albeit the methods do not write to the structures. The next commit will change related pointers to const, so this commit provides the required constness. Sponsored-by: On-Waves ehf
2015-06-22ms: Reduce DL CS level if only a few LLC bytes are leftJacob Erlbeck5-5/+69
If just a few bytes are left to send to the MS, it makes sense to reduce the coding scheme level to increase the throughput. This has been shown by Chen and Goodman in their paper "Theoretical Analysis of GPRS Throughput and Delay". See their throughput over C/I measurement graphs (figures 4 and 5 in the paper) for details. This commit implements a simplified CS downgrade feature for the downlink. The coding scheme will be downgraded if there are only a few octets are left to be send over the TBF (see the downgrade-threshold command below) and the NACK rate is not low (the CS will not get degraded on a high quality RF link). As an exception, CS-3 will be degraded to CS-1, since CS-2 does not improve the throughput in general when a few small packets are sent and the signal fades slowly (see Chen/Goodman). The following VTY command is added to the config-pcu node: - cs downgrade-threshold <1-10000> - cs no downgrade-threshold to set the threshold of the number of remaining bytes to be RLC/MAC encoded. The CS will only be reduced, if the number is below the threshold. The 'no' command disables this feature completely. The default value is 200 octets. Sponsored-by: On-Waves ehf
2015-06-22llc: Keep track of the number of stored LLC octetsJacob Erlbeck2-0/+11
To get the number of LLC octets that are stored in the queue, this commit adds a m_queue_octets member along with a octets() method. This value is updated similarly to m_queue_size on each modifying method call. Sponsored-by: On-Waves ehf
2015-06-22llc: Add missing include directive to llc.hJacob Erlbeck1-0/+4
Currently struct llist_head is used without declaration which accidently did not produce an error so far. This commit adds the missing include directive. Sponsored-by: On-Waves ehf
2015-06-22tbf: Fix downlink packet lossJacob Erlbeck2-66/+70
When the MS is pinged with a longer interval, many packets get lost even if the GprsMs object is kept. If the interval is above the time where the DL TBF is in state FLOW (mainly influenced be the dl-tbf-idle-time command), an new TBF must be requested via AGCH for each ICMP PING message. Currently the LLC frame containing the PING is immediately stored in the TBF and gets lost, if TBF establishment fails for some reason. This commit moves all calls to put_frame() to schedule_next_frame(), where the data is moved from the LLC queue to the frame storage within the TBF object. This method is only called from within create_new_bsn() when the TBF is in the FLOW state and the frame is going to be encoded immediately. At all other places, where put_frame() has been called before, the LLC message is just appended to the LLC queue in the GprsMs object. This change effectively simplifies the related code parts, since date/len information and discard notifications is no longer needed there. Ticket: #1759 Sponsored-by: On-Waves ehf
2015-06-22ms: Store the NACK rate in the MS objectJacob Erlbeck3-1/+14
Currently the NACK/unconfirmed ratio is already passed to the corresponding MS object, but the value is not being stored there. This commit adds a member and a getter method and include the values into the output of the 'show ms' command. Sponsored-by: On-Waves ehf
2015-06-22tbf: Include CS into create_new_bsn log messageJacob Erlbeck1-3/+3
This change lets the test suite fail, so it get its own commit. Sponsored-by: On-Waves ehf
2015-06-22l1: Add debug log messages for I_LEVELJacob Erlbeck1-2/+10
The I_LEVEL values that are obtained now look suspicious. They do not seem to be contained in messages recorded via gsmtab. To help debugging this issue, this commit adds related debug messages that are generated while the encoded values are taken from the RLC/MAC messages. Sponsored-by: On-Waves ehf
2015-06-22l1: Store measurement values sent by the MSJacob Erlbeck4-3/+140
This commit extends the pcu_l1_meas structure by MS side measurement values which are transmitted by PACKET DOWNLINK ACK/NACK and PACKET RESOURCE REQUEST messages. The encoded values are remapped to dB respectively % values. The values are stored in the corresponding MS object (if there is one). Note that the values are store as (rounded) integers, so some different encodings are mapped to the same decoded value. Sponsored-by: On-Waves ehf
2015-06-22ms: Add UL CS selection based on L1 link qualityJacob Erlbeck4-8/+95
Currently the UL CS values are set to the corresponding DL CS value, eventually limited by a maximum value. This approach does not reflect the general situation of the RF link between ME and BTS, which is rather asymmetric e.g. due to a lower degree of TX efficiency of the built-in antenna. This means, that UL and DL CS control should be decoupled for better results. This commit adds automatic UL CS selection based on the link quality measurement parameter. Each coding scheme is mapped to a link quality range. If the link quality value leaves that range, the current UL CS value is increased/decreased accordingly. This value will be copied when the next PACKET_UPLINK_ACK_NACK or PACKET_UPLINK_ASSIGMENT is sent to the MS. The following VTY command will be added to the config-pcu node: - cs link-quality-ranges cs1 <0-35> cs2 <0-35> <0-35> cs3 <0-35> <0-35> cs4 <0-35> which sets the ranges for the four coding schemes. For instance the example below reflects the current default values: cs link-quality-ranges cs1 6 cs2 5 8 cs3 7 13 cs4 12 set the following ranges, where the overlapping is used to configure a hysteresis: CS1: -inf .. 6 CS2: 5 .. 8 CS3: 7 .. 13 CS4: 12 .. inf Sponsored-by: On-Waves ehf
2015-06-22ms: Store the L1 measurement values in the MS objectsJacob Erlbeck4-0/+34
This commits adds the GprsMs::update_l1_meas() and GprsMs::l1_meas() methods to store and access the measurement values. The internal state is updated depending on which values are actually set. In addition, these values are shown in the output of the 'show ms imsi|tlli' command. Sponsored-by: On-Waves ehf
2015-06-22l1: Pass all L1 measurements upwardsJacob Erlbeck7-15/+70
Currently only the RSSI value is passed to the upper layers. Other values like TA and BER which are needed for TA update respectively CS selection are not propagated. This commit introduces and passes a struct that contains a set of measurement values. Sponsored-by: On-Waves ehf
2015-06-22build: Add -lrt to AM_LDFLAGSJacob Erlbeck1-0/+1
This is needed to link programs using clock_gettime and related functions when compiling with older glibc versions. This should fix the Jenkins build. Nevertheless fixing this in configure.ac were probably nicer. Sponsored-by: On-Waves ehf
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