Folks, Please direct any comments to the DISPATCH WG mailing list. Thanks, Mary. -----Original Message----- From: sipping-bounces@xxxxxxxx [mailto:sipping-bounces@xxxxxxxx] On Behalf Of Vijay K. Gurbani Sent: Wednesday, April 29, 2009 9:32 AM To: sip-ops@xxxxxxxx; dispatch@xxxxxxxx Subject: SIP-CLF: Results on ASCII vs. binary representation [Bcc'd to sipping] Hello: During the SF IETF, the SIP CLF work [2] garnered support and attention; the minutes of the ad-hoc are archived in [1]. While there was near universal support for having a common log format, there was a lot of discussion about whether the format should be text or binary, the argument for binary being that it should be much faster to search. An option for text generation is in [2] and an option for binary generation is in [3]. We realized the question is not "binary vs. text?" but "should we optimize for log generation vs. optimize for log processing?" To that extent, this email is to socialize the performance results we have obtained for generating both binary and ASCII formats, including a simulation of a worst-case analysis by retrieving the last record from large binary and ASCII files. To get these results, we generated 1 Million SIP CLF entries into an ASCII file and the same 1 Million into a binary file. The ASCII file followed the convention of [2] and the binary file that of [3]. The last entry in these files was a SIP request with a special Call-ID. We measured the time it took to search for the special Call-ID in both the binary and ASCII files. Here are the results, followed by some discussion; the source code to the programs that generated these results is also available (see [4].) Total records in binary and ASCII CLF file: 1 Million File size: Binary: 300,999,984 bytes ASCII: 258,999,984 bytes Time taken to generate the CLF file with 1 Million records: Binary CLF: 138.60s ASCII CLF: 7.26s This is a difference of almost 20x in favor of the ASCII CLF. Time taken to seek to the last record of the CLF file: Binary CLF: 3.08s ASCII CLF: 16.55s (using perl v5.6.1) 42.92s (using perl v.5.8 and v5.10) The ASCII CLF seek is five times slower using perl v5.6.1, and 13x slower using perl v5.8 and v5.10. It looks like later versions of perl may have inadvertently made the regex compiler less optimized. We don't know why. The above data is from experiments ran on an Intel dual-core (T2500 @ 2.00 GHz) IBM T60 laptop running Linux 2.6.27 with 1 GByte of memory. We also ran the programs on a more powerful machine: Intel dual-core (X6800 @ 2.93GHz) machines with 8GB RAM and a Linux 2.6.24 kernel. The results scaled accordingly. Clearly, the biggest difference in the above data is the time taken to produce the CLF file. ASCII is a lightweight approach since the SIP entity producing the ASCII CLF file already has the SIP message in text form. It is then just a matter of writing the fields out on disk. With the binary form, the SIP entity producing the binary CLF file has to calculate offsets, which takes a non-negligible amount of time. Since the entity producing the SIP CLF log file should not be over- burdened with the act of producing it, we feel that ASCII CLF generation is the only choice here (i.e., we should optimize for log generation.) Otherwise, the SIP entity producing the binary CLF file will spend an inordinate time in calculating offsets, creating a table of contents, etc. to the detriment of providing the service it is supposed to. That said, it is also clear that the the worst-case search for a record is at five to 13x slower when using ASCII. But, because searching is done offline, we feel that this sub-optimality can well be tolerated. We also feel that there is value in specifying a binary format because it allows for SIP operators who want to do such searches to convert their ASCII files to binary for optimized traversal and other such uses. A binary format must be defined so that offline processes can convert the captured ASCII data to binary format for optimized traversal. Comments and discussions on these results are welcome. If you find any errors in the programs used to generate these results, please do let us know. [1] Thread " Meeting Minutes: Ad-hoc Common Log Format meeting," IETF SIPPING WG, March 27, 2009. Archived at: http://www.ietf.org/mail-archive/web/sipping/current/msg17199.html [2] V. Gurbani, E. Burger, T. Anjali, H. Abdelnur and O. Festor, "The Common Log File (CLF) format for the Session Initiation Protocol (SIP)," IETF Internet-Draft, work in progress, March 9, 2009. Archived at: http://tools.ietf.org/html/draft-gurbani-sipping-clf-01 [3] A. Roach, "Binary Syntax for SIP Common Log Format," IETF Internet-Draft, work in progress, March 25, 2009. Archived at: http://tools.ietf.org/html/draft-roach-sipping-clf-syntax-00. [4] Source code available at the following URLs; please see comment block in clf-write.c on how to generate ASCII and binary CLF files. http://ect.bell-labs.com/who/vkg/IETF/sip-clf/write-clf.c http://ect.bell-labs.com/who/vkg/IETF/sip-clf/clf.h http://ect.bell-labs.com/who/vkg/IETF/sip-clf/read-clf-record.c http://ect.bell-labs.com/who/vkg/IETF/sip-clf/read-clf-record.pl http://ect.bell-labs.com/who/vkg/IETF/sip-clf/Makefile Thanks, - vijay -- Vijay K. Gurbani, Bell Laboratories, Alcatel-Lucent 1960 Lucent Lane, Rm. 9C-533, Naperville, Illinois 60566 (USA) Email: vkg@{alcatel-lucent.com,bell-labs.com,acm.org} Web: http://ect.bell-labs.com/who/vkg/ _______________________________________________ Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping This list is for NEW development of the application of SIP Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip Use sip@xxxxxxxx for new developments of core SIP _______________________________________________ Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping This list is for NEW development of the application of SIP Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip Use sip@xxxxxxxx for new developments of core SIP
