Snort mailing list archives
Optimized implementation of AC and AC_Q pattern matching algorithms
From: abed mohammad kamaluddin <abedamu () gmail com>
Date: Fri, 25 Jan 2013 20:29:36 +0530
Hi, I have been working on porting snort to multicore MIPs (Octeon) processors for high performance networks for which I have analyzed the existing software pattern matching algorithms. Even though the focus is on using our own proprietary hardware pattern matching engine (which gives more than double the performance of the best software algorithm), we are supporting all s/w algorithms on our port. *While profiling Aho-Corasick based search (ac and ac-q) , it was found that the number of instructions could be significantly reduced in the main loop (the AC_SEARCH macros) if the next state was pre-fetched before it was used. Each byte of Input passes through this loop, so the performance increase is significant w.r.t to the present implementation. Unexpectedly the gcc compiler is unable to perform this optimization on its own. * Though simple optimization, it translates into more than 10-14% performance jump. Also, this is not processor specific. I have tried on both 2U Dual Intel Xeon Server and OCTEON68XX (32 core CAVIUM processor) for above 20Gbps line rates and I see the bump up. Also the same behavior is observed for snort-2.9.0 to snort-2.9.4. I am attaching the patch (w.r.t snort 2.9.4) , and would like to contribute the same to OSS community. Regards -- Abed M K Software Engineer Cavium IDC
Attachment:
acsmx2_performance.patch
Description:
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Current thread:
- Optimized implementation of AC and AC_Q pattern matching algorithms abed mohammad kamaluddin (Jan 25)
- Re: Optimized implementation of AC and AC_Q pattern matching algorithms Hui Cao (Jan 26)
- Re: Optimized implementation of AC and AC_Q pattern matching algorithms abed mohammad kamaluddin (Jan 26)
- Re: Optimized implementation of AC and AC_Q pattern matching algorithms Hui Cao (Jan 26)