Before this change when GELI detected hardware crypto acceleration it will

start only one worker thread. For software crypto it will start by default
N worker threads where N is the number of available CPUs.

This is not optimal if hardware crypto is AES-NI, which uses CPU for AES
calculations.

Change that to always start one worker thread for every available CPU.
Number of worker threads per GELI provider can be easly reduced with
kern.geom.eli.threads sysctl/tunable and even for software crypto it
should be reduced when using more providers.

While here, when number of threads exceeds number of CPUs avilable don't
reduce this number, assume the user knows what he is doing.

Reported by:	Yuri Karaban <dev@dev97.com>
MFC after:	3 days

1 files changed, 4 insertions, 12 deletions

diff --git a/sys/geom/eli/g_eli.c b/sys/geom/eli/g_eli.c
index b5e4f7b6d696..874aa2689a07 100644
--- a/sys/geom/eli/g_eli.c
+++ b/sys/geom/eli/g_eli.c
@@ -443,16 +443,15 @@ g_eli_worker(void *arg)
 	sc = wr->w_softc;
 #ifdef SMP
 	/* Before sched_bind() to a CPU, wait for all CPUs to go on-line. */
-	if (mp_ncpus > 1 && sc->sc_crypto == G_ELI_CRYPTO_SW &&
-	    g_eli_threads == 0) {
+	if (sc->sc_cpubind) {
 		while (!smp_started)
 			tsleep(wr, 0, "geli:smp", hz / 4);
 	}
 #endif
 	thread_lock(curthread);
 	sched_prio(curthread, PUSER);
-	if (sc->sc_crypto == G_ELI_CRYPTO_SW && g_eli_threads == 0)
-		sched_bind(curthread, wr->w_number);
+	if (sc->sc_cpubind)
+		sched_bind(curthread, wr->w_number % mp_ncpus);
 	thread_unlock(curthread);
 
 	G_ELI_DEBUG(1, "Thread %s started.", curthread->td_proc->p_comm);
@@ -813,11 +812,7 @@ g_eli_create(struct gctl_req *req, struct g_class *mp, struct g_provider *bpp,
 	threads = g_eli_threads;
 	if (threads == 0)
 		threads = mp_ncpus;
-	else if (threads > mp_ncpus) {
-		/* There is really no need for too many worker threads. */
-		threads = mp_ncpus;
-		G_ELI_DEBUG(0, "Reducing number of threads to %u.", threads);
-	}
+	sc->sc_cpubind = (mp_ncpus > 1 && threads == mp_ncpus);
 	for (i = 0; i < threads; i++) {
 		if (g_eli_cpu_is_disabled(i)) {
 			G_ELI_DEBUG(1, "%s: CPU %u disabled, skipping.",
@@ -857,9 +852,6 @@ g_eli_create(struct gctl_req *req, struct g_class *mp, struct g_provider *bpp,
 			goto failed;
 		}
 		LIST_INSERT_HEAD(&sc->sc_workers, wr, w_next);
-		/* If we have hardware support, one thread is enough. */
-		if (sc->sc_crypto == G_ELI_CRYPTO_HW)
-			break;
 	}
 
 	/*