svn commit: r263978 - head/sys/cam/ctl

[Kubilay Kocak]

On 1/04/2014 7:49 AM, Edward Tomasz Napierala wrote:
> Author: trasz
> Date: Mon Mar 31 20:49:33 2014
> New Revision: 263978
> URL: http://svnweb.freebsd.org/changeset/base/263978
> 
> Log:
>   Make it possible to have multiple CTL worker threads.  Leave the default
>   of 1 for now.
>   
>   Sponsored by:	The FreeBSD Foundation
> 
> Modified:
>   head/sys/cam/ctl/ctl.c
> 
> Modified: head/sys/cam/ctl/ctl.c
> ==============================================================================
> --- head/sys/cam/ctl/ctl.c	Mon Mar 31 19:58:08 2014	(r263977)
> +++ head/sys/cam/ctl/ctl.c	Mon Mar 31 20:49:33 2014	(r263978)
> @@ -60,6 +60,7 @@ __FBSDID("$FreeBSD$");
>  #include <sys/ioccom.h>
>  #include <sys/queue.h>
>  #include <sys/sbuf.h>
> +#include <sys/smp.h>
>  #include <sys/endian.h>
>  #include <sys/sysctl.h>
>  
> @@ -320,6 +321,10 @@ static int     ctl_is_single = 1;
>  static int     index_to_aps_page;
>  
>  SYSCTL_NODE(_kern_cam, OID_AUTO, ctl, CTLFLAG_RD, 0, "CAM Target Layer");
> +static int worker_threads = 1;
> +TUNABLE_INT("kern.cam.ctl.worker_threads", &worker_threads);
> +SYSCTL_INT(_kern_cam_ctl, OID_AUTO, worker_threads, CTLFLAG_RDTUN,
> +    &worker_threads, 1, "Number of worker threads");
>  
>  /*
>   * Serial number (0x80), device id (0x83), and supported pages (0x00)
> @@ -950,10 +955,7 @@ ctl_init(void)
>  	struct ctl_frontend *fe;
>  	struct ctl_lun *lun;
>          uint8_t sc_id =0;
> -#if 0
> -	int i;
> -#endif
> -	int error, retval;
> +	int i, error, retval;
>  	//int isc_retval;
>  
>  	retval = 0;
> @@ -1085,17 +1087,35 @@ ctl_init(void)
>  	mtx_unlock(&softc->ctl_lock);
>  #endif
>  
> -	error = kproc_create(ctl_work_thread, softc, &softc->work_thread, 0, 0,
> -			 "ctl_thrd");
> -	if (error != 0) {
> -		printf("error creating CTL work thread!\n");
> -		mtx_lock(&softc->ctl_lock);
> -		ctl_free_lun(lun);
> -		mtx_unlock(&softc->ctl_lock);
> -		ctl_pool_free(internal_pool);
> -		ctl_pool_free(emergency_pool);
> -		ctl_pool_free(other_pool);
> -		return (error);
> +	if (worker_threads > MAXCPU || worker_threads == 0) {
> +		printf("invalid kern.cam.ctl.worker_threads value; "
> +		    "setting to 1");
> +		worker_threads = 1;
> +	} else if (worker_threads < 0) {

Why is it that the < 0 case is special enough that it gets the mp_ncpus
check below, but the == 0 and > MAXCPU cases don't?

> +		if (mp_ncpus > 2) {
> +			/*
> +			 * Using more than two worker threads actually hurts
> +			 * performance due to lock contention.
> +			 */

> +			worker_threads = 2;
> +		} else {
> +			worker_threads = 1;
> +		}

Are printf("Setting to N")'s worthwhile here as well given
worker_threads is set to a value that wasn't specified by the user, as
above?

> +	}
> +
> +	for (i = 0; i < worker_threads; i++) {
> +		error = kproc_create(ctl_work_thread, softc, &softc->work_thread, 0, 0,
> +				"ctl_thrd%d", i);
> +		if (error != 0) {
> +			printf("error creating CTL work thread!\n");
> +			mtx_lock(&softc->ctl_lock);
> +			ctl_free_lun(lun);
> +			mtx_unlock(&softc->ctl_lock);
> +			ctl_pool_free(internal_pool);
> +			ctl_pool_free(emergency_pool);
> +			ctl_pool_free(other_pool);
> +			return (error);
> +		}
>  	}
>  	if (bootverbose)
>  		printf("ctl: CAM Target Layer loaded\n");
> @@ -12991,7 +13011,11 @@ ctl_work_thread(void *arg)
>  			if (io != NULL) {
>  				STAILQ_REMOVE_HEAD(&softc->rtr_queue, links);
>  				mtx_unlock(&softc->ctl_lock);
> -				goto execute;
> +				retval = ctl_scsiio(&io->scsiio);
> +				if (retval != CTL_RETVAL_COMPLETE)
> +					CTL_DEBUG_PRINT(("ctl_scsiio failed\n"));
> +				mtx_lock(&softc->ctl_lock);
> +				continue;
>  			}
>  		}
>  		io = (union ctl_io *)STAILQ_FIRST(&softc->incoming_queue);
> @@ -13022,19 +13046,6 @@ ctl_work_thread(void *arg)
>  
>  		/* Back to the top of the loop to see what woke us up. */
>  		continue;
> -
> -execute:
> -		retval = ctl_scsiio(&io->scsiio);
> -		switch (retval) {
> -		case CTL_RETVAL_COMPLETE:
> -			break;
> -		default:
> -			/*
> -			 * Probably need to make sure this doesn't happen.
> -			 */
> -			break;
> -		}
> -		mtx_lock(&softc->ctl_lock);
>  	}
>  }
>  
> _______________________________________________
> svn-src-head at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/svn-src-head
> To unsubscribe, send any mail to "svn-src-head-unsubscribe at freebsd.org"
>