[Oisf-users] Detect_Thread_Ratio

[Will Metcalf]

> Do I get a star?

A gold one :D...

Regards,

Will

On Fri, Aug 12, 2011 at 10:26 PM, Gene Albin <gene.albin at gmail.com> wrote:
> Ah soo.  It appears that when taking a float and making it an int it rounds
> down.  So when I set my detect_thread_ratio values at .1, .2, .3, .4, .5,
> .6, .7, .8, .9, I will get 4, 9, 14, 19, 24, 28, 33, 38, and 43
> respectively.
>
> Do I get a star?
> Gene
>
> On Fri, Aug 12, 2011 at 4:05 PM, Will Metcalf <william.metcalf at gmail.com>
> wrote:
>>
>> I did leave out this piece...
>>
>> src/runmodes.h:extern float threading_detect_ratio;
>>
>> It is key...
>>
>> mmmmm grasshopper the answer lies in the code below...
>>
>> gcc -o makin-stuff makin-stuff.c
>> ./makin-stuff
>>
>> --------snip---------------
>> #include <stdio.h>
>>
>> main(){
>>    int foo = 48;
>>    float bar = 0.2;
>>    int blat;
>>
>>    blat = foo * bar;
>>    printf("where did my remainder go? %i\n", blat);
>>
>>    printf("how many do we make?\n");
>>    int i;
>>    for (i = 0; i < blat; i++) {
>>       printf("%i\n", i +1);
>>    }
>>    return 0;
>> }
>>
>>
>>
>> On Fri, Aug 12, 2011 at 5:10 PM, Gene Albin <gene.albin at gmail.com> wrote:
>> > Ok, so if I'm reading that right (and it's like reading
>> > ancient hieroglyphics to me!) it looks like first we will never have
>> > less
>> > than 1 thread, and second we are working with integers so no decimals.
>> >  If
>> > that is the case, then does the 'int' function round decimals to the
>> > nearest
>> > integer or does it round all down?  I don't see anything there forcing
>> > it to
>> > round down so I'd assume it rounds to the nearest.
>> > So my 'homework' answer would be that it uses integers and rounds to the
>> > nearest integer > 0.
>> > How'd I do, teach?
>> > Gene
>> > On Fri, Aug 12, 2011 at 2:59 PM, Will Metcalf
>> > <william.metcalf at gmail.com>
>> > wrote:
>> >>
>> >> Since this all sounds a bit like a homework assignment you tell me :D?
>> >>
>> >>   * threads we're not creating the most on CPU0. */
>> >>    if (ncpus > 0)
>> >>        cpu = 1;
>> >>
>> >>    /* always create at least one thread */
>> >>    int thread_max = TmThreadGetNbThreads(DETECT_CPU_SET);
>> >>    if (thread_max == 0)
>> >>        thread_max = ncpus * threading_detect_ratio;
>> >>    if (thread_max < 1)
>> >>        thread_max = 1;
>> >>
>> >>    int thread;
>> >>    for (thread = 0; thread < thread_max; thread++) {
>> >>        snprintf(tname, sizeof(tname), "Detect%"PRIu16, thread+1);
>> >>
>> >>        char *thread_name = SCStrdup(tname);
>> >>        SCLogDebug("Assigning %s affinity to cpu %u", thread_name, cpu);
>> >>
>> >>        ThreadVars *tv_detect_ncpu =
>> >>            TmThreadCreatePacketHandler(thread_name,
>> >>                                        "stream-queue1", "simple",
>> >>                                        "alert-queue1", "simple",
>> >>                                        "1slot");
>> >>        if (tv_detect_ncpu == NULL) {
>> >>            printf("ERROR: TmThreadsCreate failed\n");
>> >>            exit(EXIT_FAILURE);
>> >>        }
>> >>        tm_module = TmModuleGetByName("Detect");
>> >>        if (tm_module == NULL) {
>> >>            printf("ERROR: TmModuleGetByName Detect failed\n");
>> >>            exit(EXIT_FAILURE);
>> >>        }
>> >>        Tm1SlotSetFunc(tv_detect_ncpu, tm_module, (void *)de_ctx);
>> >>
>> >>        TmThreadSetCPU(tv_detect_ncpu, DETECT_CPU_SET);
>> >>
>> >>        char *thread_group_name = SCStrdup("Detect");
>> >>        if (thread_group_name == NULL) {
>> >>            printf("Error allocating memory\n");
>> >>            exit(EXIT_FAILURE);
>> >>        }
>> >>        tv_detect_ncpu->thread_group_name = thread_group_name;
>> >>
>> >>        if (TmThreadSpawn(tv_detect_ncpu) != TM_ECODE_OK) {
>> >>            printf("ERROR: TmThreadSpawn failed\n");
>> >>            exit(EXIT_FAILURE);
>> >>        }
>> >>
>> >>        if ((cpu + 1) == ncpus)
>> >>            cpu = 0;
>> >>        else
>> >>            cpu++;
>> >>    }
>> >>
>> >>
>> >> On Fri, Aug 12, 2011 at 4:38 PM, Gene Albin <gene.albin at gmail.com>
>> >> wrote:
>> >> > I understand that the detect_thread_ratio in the suricata.yaml file
>> >> > determines the number of threads created by multiplying the ratio
>> >> > number
>> >> > by
>> >> > the number of CPU cores.  What does Suricata do when the result is
>> >> > not
>> >> > an
>> >> > integer?  For example .2*48=9.6.  Is this rounded down to the lowest
>> >> > integer?  Does it create 9.6 threads?  Does it round up?
>> >> >
>> >> > Thanks,
>> >> > --
>> >> > Gene Albin
>> >> > gene.albin at gmail.com
>> >> >
>> >> >
>> >> > _______________________________________________
>> >> > Oisf-users mailing list
>> >> > Oisf-users at openinfosecfoundation.org
>> >> > http://lists.openinfosecfoundation.org/mailman/listinfo/oisf-users
>> >> >
>> >> >
>> >
>> >
>> >
>> > --
>> > Gene Albin
>> > gene.albin at gmail.com
>> >
>> >
>
>
>
> --
> Gene Albin
> gene.albin at gmail.com
>
>