RE: [PATCH v4] Add git-grep threads param

From: Victor Leschuk <vleschuk@accesssoftek.com>
Date: Nov 9, 2015, 16:34 UTC
Message-ID: <6AE1604EE3EC5F4296C096518C6B77EE5D0FDABA17@mail.accesssoftek.com>
In-Reply-To: <20151109155538.GC27224@sigill.intra.peff.net>

> Why don't we leave it at 8, then? That's the conservative choice, and
> once we have --threads, people can easily experiment with different
> values and we can follow-up with a change to the default if need be.

I'd propose the following:

    if (list.nr || cached) {                                                                                            
        num_threads = 0; /* Can not multi-thread object lookup */                                                       
    }                                                                                                                   
    else if (num_threads < 0 && online_cpus() <= 1) {                                                                   
        num_threads = 0; /* User didn't set threading option and we have <= 1 of hardware cores */                      
    }                                                                                                                   
    else if (num_threads == 0) {                                                                                        
        num_threads = GREP_NUM_THREADS_DEFAULT; /* User explicitly choose default behavior */                           
    }                                                                                                                   
    else if (num_threads < 0) {  /* Actually this one should be checked earlier so no need to double check here */                                                                                       
        die(_("Ivalid number of threads specified (%d)"), num_threads)                                                  
    }

-- Victor