Energy-Efficient Ranking on FPGAs through
Ensemble Model Compression (Abstract)
Veronica Gil-Costa1 , Fernando Loor1 , Romina Molina1,2,3 , Franco Maria Nardini3 ,
Raffaele Perego3 and Salvatore Trani3
1
  Universidad Nacional de San Luis, San Luis, Argentina
2
  Università degli Studi di Trieste, Trieste, Italy
3
  ISTI-CNR, Pisa, Italy



   In this talk we present the main results of a paper accepted at ECIR 2022 [1].
We investigate novel SoC-FPGA solutions for fast and energy-efficient ranking based on machine-
learned ensembles of decision trees. Since the memory footprint of ranking ensembles limits the
effective exploitation of programmable logic for large-scale inference tasks [2], we investigate
binning and quantization techniques to reduce the memory occupation of the learned model
and we optimize the state-of-the-art ensemble-traversal algorithm for deployment on low-
cost, energy-efficient FPGA devices. The results of the experiments conducted using publicly
available Learning-to-Rank datasets, show that our model compression techniques do not impact
significantly the accuracy. Moreover, the reduced space requirements allow the models and
the logic to be replicated on the FPGA device in order to execute several inference tasks in
parallel. We discuss in details the experimental settings and the feasibility of the deployment
of the proposed solution in a real setting. The results of the experiments conducted show that
our FPGA solution achieves performances at the state of the art and consumes from 9× up to
19.8× less energy than an equivalent multi-threaded CPU implementation.


References
[1] V. Gil-Costa, F. Loor, R. Molina, F. M. Nardini, R. Perego, S. Trani, Ensemble model compres-
    sion for fast and energy-efficient ranking on fpgas, in: European Conference on Information
    Retrieval, Springer, 2022, pp. 260–273.
[2] R. Molina, F. Loor, V. Gil-Costa, F. M. Nardini, R. Perego, S. Trani, Efficient traversal of
    decision tree ensembles with FPGAs, Journal of Parallel and Distributed Computing 155
    (2021) 38–49.



IIR2022: 12th Italian Information Retrieval Workshop, June 29 - June 30th, 2022, Milan, Italy
" gvcosta@unsl.edu.ar (V. Gil-Costa); fernandoloor1@gmail.com (F. Loor); mromy00@gmail.com (R. Molina);
francomaria.nardini@isti.cnr.it (F. M. Nardini); raffaele.perego@isti.cnr.it (R. Perego); salvatore.trani@isti.cnr.it
(S. Trani)
 0000-0003-4637-9725 (V. Gil-Costa); 0000-0002-8552-1221 (F. Loor); 0000-0001-7688-6248 (R. Molina);
0000-0003-3183-334X (F. M. Nardini); 0000-0001-7189-4724 (R. Perego); 0000-0001-6541-9409 (S. Trani)
                                       © 2022 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
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