Calling runtime PM API for every block causes serious perf hit to
crypto operations that are done on a long buffer.
As crypto is performed on a page boundary, encrypting large buffers can
cause a series of crypto operations divided by page. The runtime PM API
is also called those many times.
We call runtime_pm_get_sync only at beginning on the session (cra_init)
and runtime_pm_put at the end. This result in upto a 50% speedup as below.
This doesn't make the driver to keep the system awake as runtime get/put
is only called during a crypto session which completes usually quickly.
Before:
root@beagleboard:~# time -v openssl speed -evp aes-128-cbc
Doing aes-128-cbc for 3s on 16 size blocks: 13310 aes-128-cbc's in 0.01s
Doing aes-128-cbc for 3s on 64 size blocks: 13040 aes-128-cbc's in 0.04s
Doing aes-128-cbc for 3s on 256 size blocks: 9134 aes-128-cbc's in 0.03s
Doing aes-128-cbc for 3s on 1024 size blocks: 8939 aes-128-cbc's in 0.01s
Doing aes-128-cbc for 3s on 8192 size blocks: 4299 aes-128-cbc's in 0.00s
After:
root@beagleboard:~# time -v openssl speed -evp aes-128-cbc
Doing aes-128-cbc for 3s on 16 size blocks: 18911 aes-128-cbc's in 0.02s
Doing aes-128-cbc for 3s on 64 size blocks: 18878 aes-128-cbc's in 0.02s
Doing aes-128-cbc for 3s on 256 size blocks: 11878 aes-128-cbc's in 0.10s
Doing aes-128-cbc for 3s on 1024 size blocks: 11538 aes-128-cbc's in 0.05s
Doing aes-128-cbc for 3s on 8192 size blocks: 4857 aes-128-cbc's in 0.03s
While at it, also drop enter and exit pr_debugs, in related code. tracers
can be used for that.
Tested on a Beaglebone (AM335x SoC) board.
v3 changes:
Refreshed patch on kernel v3.10-rc3
Signed-off-by: Joel A Fernandes <joelagnel@xxxxxx>
---
drivers/crypto/omap-aes.c | 29 +++++++++++++++++++----------
1 files changed, 19 insertions(+), 10 deletions(-)
diff --git a/drivers/crypto/omap-aes.c b/drivers/crypto/omap-aes.c
index ee15b0f..06524a0 100644
--- a/drivers/crypto/omap-aes.c
+++ b/drivers/crypto/omap-aes.c
@@ -203,13 +203,6 @@ static void omap_aes_write_n(struct omap_aes_dev *dd, u32 offset,
static int omap_aes_hw_init(struct omap_aes_dev *dd)
{
- /*
- * clocks are enabled when request starts and disabled when finished.
- * It may be long delays between requests.
- * Device might go to off mode to save power.
- */
- pm_runtime_get_sync(dd->dev);
-
if (!(dd->flags & FLAGS_INIT)) {
dd->flags |= FLAGS_INIT;
dd->err = 0;
@@ -636,7 +629,6 @@ static void omap_aes_finish_req(struct omap_aes_dev *dd, int err)
pr_debug("err: %d\n", err);
- pm_runtime_put(dd->dev);
dd->flags &= ~FLAGS_BUSY;
req->base.complete(&req->base, err);
@@ -837,8 +829,16 @@ static int omap_aes_ctr_decrypt(struct ablkcipher_request *req)
static int omap_aes_cra_init(struct crypto_tfm *tfm)
{
- pr_debug("enter\n");
+ struct omap_aes_dev *dd = NULL;
+ /* Find AES device, currently picks the first device */
+ spin_lock_bh(&list_lock);
+ list_for_each_entry(dd, &dev_list, list) {
+ break;
+ }
+ spin_unlock_bh(&list_lock);
+
+ pm_runtime_get_sync(dd->dev);
tfm->crt_ablkcipher.reqsize = sizeof(struct omap_aes_reqctx);
return 0;
@@ -846,7 +846,16 @@ static int omap_aes_cra_init(struct crypto_tfm *tfm)
static void omap_aes_cra_exit(struct crypto_tfm *tfm)
{
- pr_debug("enter\n");
+ struct omap_aes_dev *dd = NULL;
+
+ /* Find AES device, currently picks the first device */
+ spin_lock_bh(&list_lock);
+ list_for_each_entry(dd, &dev_list, list) {
+ break;
+ }
+ spin_unlock_bh(&list_lock);
+
+ pm_runtime_put_sync(dd->dev);
}
/* ********************** ALGS ************************************ */
--
1.7.4.1
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