Re: Optimized implementation of AC and AC_Q pattern matching algorithms

[abed mohammad kamaluddin <abedamu () gmail com>]

Hi Pablo,

I tried you modification on OCTEON today and was disappointed that
there was a drop in performance on it, however on Intel there is
significant improvement in perf. In comparison to unmodified snort
using Network traffic and ac-q:

                                      cross-compiling (Octeon)
      gcc (Intel)
Using your modification - 15% down                                      21% up
Using mine                  -  11% up
       12% up


On Intel, we can remove sindex altogether:

       state = ps[2 + xlatcase[T[0]]]

Maybe it could be because I am cross compiling ; there were lot of
wasted cycles in my case. Unless I introduce an intermediate state, I
am not getting any improvement. I had earlier analyzed this routine in
detail and each cycle reduced in this macro gave significant perf
improvements.

Could you please mention the following:
- Which compiler have you used (gcc/icc version).
- If you can provide the pcap file you are using for the tests it would help.

I will try your modifications on a bigger Intel machine sometime this
week and report the findings.

Thanks,
Abed M K


On Sun, Jan 27, 2013 at 12:27 AM, abed mohammad kamaluddin
<abedamu () gmail com> wrote:
> Hi Pablo,
>
> That looks neater :) I will try your modifications on our system on Monday
> when I return to work. I used zero-alert traffic to measure perf which gave
> me 11% up on 2.9.0.4.
>
> PS: I have noticed a more than 15% overall performance drop on 2.9.4 as
> compare to 2.9.3.1 when compiled with exactly same options. I haven't
> analyzed it so far, however this particular optimization has the same
> relative improvement on all versions (2.9.0.4, 2.9.3.1 and 2.9.4) .
>
> Thanks,
> Abed
>
>
>
> Message: 2
> > Date: Sat, 26 Jan 2013 16:50:37 +0100
> > From: Pablo Cantos <pablocantos () gmail com>
> > Subject: Re: [Snort-devel] Optimized implementation of AC and AC_Q
> >         pattern matching algorithms
> > To: snort-devel () lists sourceforge net
> > Message-ID:
> >
> > <CADQcQ1OzJDso9FEQhG77dGtSTEiX=J80bxRDMv9t8Yz7WhH0-g () mail gmail com>
> > Content-Type: text/plain; charset="iso-8859-1"
> >
> > Hi Abed,
> >
> > First of all, thanks for your contribution.
> >
> > I have checked your proposal in snort 2.9.1 by using two different pcap
> > files, one of them (612MB-sized) throws around 900k alerts and the other
> > one (1GB-sized) throws just 55 alerts. I have used an AMD Turion II
> > dual-core mobile M520 at 2.3GHz, 512KB cache L2 by each core and 4GB RAM.
> >
> > These are the performance jumps that I have obtained:
> >
> > 612MB file -> 4.24% for MPSE, 5.93% for ac-q
> > 1GB file -> 7.93% for MPSE, 8.03% for ac-q
> >
> > These results were obtained by measuring the times taken to analyze each
> > pcap file by the MPSE and AC, separately.
> >
> > I have been working for several months with Snort to get improvements in
> > other areas of the MPSE, I have also studied the AC_SEARCH macros and I
> > didn't find them completely efficients but I didn't go further. Now,
> > after
> > seeing your proposal and checking the AC_SEARCH_Q again I thought that
> > taking small changes it could work even better.
> >
> > You have suggested to pre-fetch the new state before was used it:
> >
> > #define AC_SEARCH_Q \
> > +   *acstate_t new_state;* \
> >     for (; T < Tend; T++) \
> >     { \
> >         ps = NextState[state]; \
> >         sindex = xlatcase[T[0]]; \
> > +       *new_state = ps[2 + sindex];*  \
> >         if (ps[1]) \
> >         { \
> >             if (MatchList[state]) \
> >             { \
> >                 if (_add_queue(&acsm->q,MatchList[state])) \
> >                 { \
> >                     if (_process_queue(&acsm->q, Match,data)) \
> >                     { \
> >                         *current_state = state; \
> >                         return 1; \
> >                     } \
> >                 } \
> >             } \
> >         } \
> > *-       state = ps[2 + sindex]; \
> > *
> > +       *state = new_state;* \
> >     }
> >  #endif
> >
> > But I think the routine could be more efficient too if we just fetch the
> > new state in the end, and we move down one line:
> >
> > #define AC_SEARCH_Q \
> >     for (; T < Tend; T++) \
> >     { \
> >         ps = NextState[state]; \
> > *-       sindex = xlatcase[T[0]]; \*
> >         if (ps[1]) \
> >         { \
> >             if (MatchList[state]) \
> >             { \
> >                 if (_add_queue(&acsm->q,MatchList[state])) \
> >                 { \
> >                     if (_process_queue(&acsm->q, Match,data)) \
> >                     { \
> >                         *current_state = state; \
> >                         return 1; \
> >                     } \
> >                 } \
> >             } \
> >         } \
> > *+       sindex = xlatcase[T[0]]; \*
> >         state = ps[2 + sindex]; \
> >     }
> > #endif
> >
> > In this way, I think the number of instructions could be reduced too.
> >
> > And these are the results that I have obtained:
> >
> > 612MB file -> 15.66% for MPSE, 22.13% for ac-q
> > 1GB file -> 34.49% for MPSE, 35.13% for ac-q
> >
> > I will try to repeat these tests using other more powerful computers. In
> > any case, we will give more information on Monday.
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
> >
> > ------------------------------
> >
> > Message: 3
> > Date: Sat, 26 Jan 2013 11:26:55 -0500
> > From: Joel Esler <jesler () sourcefire com>
> > Subject: Re: [Snort-devel] Optimized implementation of AC and AC_Q
> >         pattern matching algorithms
> > To: Pablo Cantos <pablocantos () gmail com>
> > Cc: "snort-devel () lists sourceforge net"
> >         <snort-devel () lists sourceforge net>
> > Message-ID: <2B25430D-9736-49BB-9A81-EC9AF163C28F () sourcefire com>
> > Content-Type: text/plain; charset="utf-8"
> >
> > Pablo,
> >
> > Great stuff. We need to make sure we are testing and modifying against
> > 2.9.4 though.
> >
> > --
> > Joel Esler
> > Sent from my iPhone ?
> >
> > On Jan 26, 2013, at 10:50 AM, Pablo Cantos <pablocantos () gmail com> wrote:
> >
> > > Hi Abed,
> > >
> > > First of all, thanks for your contribution.
> > >
> > > I have checked your proposal in snort 2.9.1 by using two different pcap
> > > files, one of them (612MB-sized) throws around 900k alerts and the other one
> > > (1GB-sized) throws just 55 alerts. I have used an AMD Turion II dual-core
> > > mobile M520 at 2.3GHz, 512KB cache L2 by each core and 4GB RAM.
> > >
> > > These are the performance jumps that I have obtained:
> > >
> > > 612MB file -> 4.24% for MPSE, 5.93% for ac-q
> > > 1GB file -> 7.93% for MPSE, 8.03% for ac-q
> > >
> > > These results were obtained by measuring the times taken to analyze
> > > each pcap file by the MPSE and AC, separately.
> > >
> > > I have been working for several months with Snort to get improvements
> > > in other areas of the MPSE, I have also studied the AC_SEARCH macros and I
> > > didn't find them completely efficients but I didn't go further. Now, after
> > > seeing your proposal and checking the AC_SEARCH_Q again I thought that
> > > taking small changes it could work even better.
> > >
> > > You have suggested to pre-fetch the new state before was used it:
> > >
> > > #define AC_SEARCH_Q \
> > > +   acstate_t new_state; \
> > >     for (; T < Tend; T++) \
> > >     { \
> > >         ps = NextState[state]; \
> > >         sindex = xlatcase[T[0]]; \
> > > +       new_state = ps[2 + sindex];  \
> > >         if (ps[1]) \
> > >         { \
> > >             if (MatchList[state]) \
> > >             { \
> > >                 if (_add_queue(&acsm->q,MatchList[state])) \
> > >                 { \
> > >                     if (_process_queue(&acsm->q, Match,data)) \
> > >                     { \
> > >                         *current_state = state; \
> > >                         return 1; \
> > >                     } \
> > >                 } \
> > >             } \
> > >         } \
> > > -       state = ps[2 + sindex]; \
> > > +       state = new_state; \
> > >     }
> > > #endif
> > >
> > > But I think the routine could be more efficient too if we just fetch
> > > the new state in the end, and we move down one line:
> > >
> > > #define AC_SEARCH_Q \
> > >     for (; T < Tend; T++) \
> > >     { \
> > >         ps = NextState[state]; \
> > > -       sindex = xlatcase[T[0]]; \
> > >         if (ps[1]) \
> > >         { \
> > >             if (MatchList[state]) \
> > >             { \
> > >                 if (_add_queue(&acsm->q,MatchList[state])) \
> > >                 { \
> > >                     if (_process_queue(&acsm->q, Match,data)) \
> > >                     { \
> > >                         *current_state = state; \
> > >                         return 1; \
> > >                     } \
> > >                 } \
> > >             } \
> > >         } \
> > > +       sindex = xlatcase[T[0]]; \
> > >         state = ps[2 + sindex]; \
> > >     }
> > > #endif
> > >
> > > In this way, I think the number of instructions could be reduced too.
> > >
> > > And these are the results that I have obtained:
> > >
> > > 612MB file -> 15.66% for MPSE, 22.13% for ac-q
> > > 1GB file -> 34.49% for MPSE, 35.13% for ac-q
> > >
> > > I will try to repeat these tests using other more powerful computers.
> > > In any case, we will give more information on Monday.
> >
> > > ------------------------------------------------------------------------------
> > > Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS,
> > > MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current
> > > with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft
> > > MVPs and experts. ON SALE this month only -- learn more at:
> > > http://p.sf.net/sfu/learnnow-d2d
> > > _______________________________________________
> > > Snort-devel mailing list
> > > Snort-devel () lists sourceforge net
> > > https://lists.sourceforge.net/lists/listinfo/snort-devel
> > > Archive:
> > > http://sourceforge.net/mailarchive/forum.php?forum_name=snort-devel
> > >
> > > Please visit http://blog.snort.org for the latest news about Snort!
> > -------------- next part --------------
> > An HTML attachment was scrubbed...
> >
> > ------------------------------
> >
> >
> >
> > ------------------------------------------------------------------------------
> > Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS,
> > MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current
> > with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft
> > MVPs and experts. ON SALE this month only -- learn more at:
> > http://p.sf.net/sfu/learnnow-d2d
> >
> > ------------------------------
> >
> >
> > _______________________________________________
> > Snort-devel mailing list
> > Snort-devel () lists sourceforge net
> > https://lists.sourceforge.net/lists/listinfo/snort-devel
> >
> >
> > End of Snort-devel Digest, Vol 78, Issue 10
> > *******************************************

------------------------------------------------------------------------------
Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS,
MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current
with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft
MVPs and experts. ON SALE this month only -- learn more at:
http://p.sf.net/sfu/learnnow-d2d
_______________________________________________
Snort-devel mailing list
Snort-devel () lists sourceforge net
https://lists.sourceforge.net/lists/listinfo/snort-devel
Archive:
http://sourceforge.net/mailarchive/forum.php?forum_name=snort-devel

Please visit http://blog.snort.org for the latest news about Snort!