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) {
+ if (mp_ncpus > 2) {
+ /*
+ * Using more than two worker threads actually hurts
+ * performance due to lock contention.
+ */
+ worker_threads = 2;
+ } else {
+ worker_threads = 1;
+ }
+ }
+
+ 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);
}
}
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