Commit 2b163b5b authored by Horia Geantă's avatar Horia Geantă Committed by Herbert Xu

Revert "crypto: caam - get rid of tasklet"

This reverts commit 66d2e202.

Quoting from Russell's findings:

Okay, I've re-tested, using a different way of measuring, because using
openssl speed is impractical for off-loaded engines.  I've decided to
use this way to measure the performance:

dd if=/dev/zero bs=1048576 count=128 | /usr/bin/time openssl dgst -md5

For the threaded IRQs case gives:

0.05user 2.74system 0:05.30elapsed 52%CPU (0avgtext+0avgdata 2400maxresident)k
0.06user 2.52system 0:05.18elapsed 49%CPU (0avgtext+0avgdata 2404maxresident)k
0.12user 2.60system 0:05.61elapsed 48%CPU (0avgtext+0avgdata 2460maxresident)k
	=> 5.36s => 25.0MB/s

and the tasklet case:

0.08user 2.53system 0:04.83elapsed 54%CPU (0avgtext+0avgdata 2468maxresident)k
0.09user 2.47system 0:05.16elapsed 49%CPU (0avgtext+0avgdata 2368maxresident)k
0.10user 2.51system 0:04.87elapsed 53%CPU (0avgtext+0avgdata 2460maxresident)k
	=> 4.95 => 27.1MB/s

which corresponds to an 8% slowdown for the threaded IRQ case.  So,
tasklets are indeed faster than threaded IRQs.


I think I've proven from the above that this patch needs to be reverted
due to the performance regression, and that there _is_ most definitely
a deterimental effect of switching from tasklets to threaded IRQs.
Signed-off-by: default avatarHoria Geantă <>
Signed-off-by: default avatarHerbert Xu <>
parent c73e36e8
......@@ -41,6 +41,7 @@ struct caam_drv_private_jr {
struct device *dev;
int ridx;
struct caam_job_ring __iomem *rregs; /* JobR's register space */
struct tasklet_struct irqtask;
int irq; /* One per queue */
/* Number of scatterlist crypt transforms active on the JobR */
......@@ -73,6 +73,8 @@ static int caam_jr_shutdown(struct device *dev)
ret = caam_reset_hw_jr(dev);
/* Release interrupt */
free_irq(jrp->irq, dev);
......@@ -128,7 +130,7 @@ static irqreturn_t caam_jr_interrupt(int irq, void *st_dev)
* Check the output ring for ready responses, kick
* the threaded irq if jobs done.
* tasklet if jobs done.
irqstate = rd_reg32(&jrp->rregs->jrintstatus);
if (!irqstate)
......@@ -150,13 +152,18 @@ static irqreturn_t caam_jr_interrupt(int irq, void *st_dev)
/* Have valid interrupt at this point, just ACK and trigger */
wr_reg32(&jrp->rregs->jrintstatus, irqstate);
static irqreturn_t caam_jr_threadirq(int irq, void *st_dev)
/* Deferred service handler, run as interrupt-fired tasklet */
static void caam_jr_dequeue(unsigned long devarg)
int hw_idx, sw_idx, i, head, tail;
struct device *dev = st_dev;
struct device *dev = (struct device *)devarg;
struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
void (*usercall)(struct device *dev, u32 *desc, u32 status, void *arg);
u32 *userdesc, userstatus;
......@@ -230,8 +237,6 @@ static irqreturn_t caam_jr_threadirq(int irq, void *st_dev)
/* reenable / unmask IRQs */
clrsetbits_32(&jrp->rregs->rconfig_lo, JRCFG_IMSK, 0);
......@@ -389,10 +394,11 @@ static int caam_jr_init(struct device *dev)
jrp = dev_get_drvdata(dev);
tasklet_init(&jrp->irqtask, caam_jr_dequeue, (unsigned long)dev);
/* Connect job ring interrupt handler. */
error = request_threaded_irq(jrp->irq, caam_jr_interrupt,
caam_jr_threadirq, IRQF_SHARED,
dev_name(dev), dev);
error = request_irq(jrp->irq, caam_jr_interrupt, IRQF_SHARED,
dev_name(dev), dev);
if (error) {
dev_err(dev, "can't connect JobR %d interrupt (%d)\n",
jrp->ridx, jrp->irq);
......@@ -454,6 +460,7 @@ static int caam_jr_init(struct device *dev)
free_irq(jrp->irq, dev);
return error;
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