Re: [PATCH 02/28] crypto: omap-sham: Don't idle/start SHA device between Encrypt operations

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On 06/01/2016 04:53 AM, Grygorii Strashko wrote:
On 06/01/2016 11:56 AM, Tero Kristo wrote:
From: Lokesh Vutla <lokeshvutla@xxxxxx>

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.
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.

Signed-off-by: Lokesh Vutla <lokeshvutla@xxxxxx>
Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
---
  drivers/crypto/omap-sham.c | 27 +++++++++++++++++----------
  1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/drivers/crypto/omap-sham.c b/drivers/crypto/omap-sham.c
index 6eefaa2..bd0258f 100644
--- a/drivers/crypto/omap-sham.c
+++ b/drivers/crypto/omap-sham.c
@@ -360,14 +360,6 @@ static void omap_sham_copy_ready_hash(struct
ahash_request *req)

  static int omap_sham_hw_init(struct omap_sham_dev *dd)
  {
-    int err;
-
-    err = pm_runtime_get_sync(dd->dev);
-    if (err < 0) {
-        dev_err(dd->dev, "failed to get sync: %d\n", err);
-        return err;
-    }
-

Would it be worth it to investigate a pm_runtime autosuspend approach rather than knocking runtime PM out here completely? I am not clear if the overhead is coming from the pm_runtime calls themselves or the actual idling of the IP, but if it's the idling of the IP causing the slowdown, with a large enough autosuspend_delay we don't actually sleep between each block but after a long enough period of idle time we would actually suspend.

Regards,
Dave

      if (!test_bit(FLAGS_INIT, &dd->flags)) {
          set_bit(FLAGS_INIT, &dd->flags);
          dd->err = 0;
@@ -999,8 +991,6 @@ static void omap_sham_finish_req(struct
ahash_request *req, int err)
      dd->flags &= ~(BIT(FLAGS_BUSY) | BIT(FLAGS_FINAL) |
BIT(FLAGS_CPU) |
              BIT(FLAGS_DMA_READY) | BIT(FLAGS_OUTPUT_READY));

-    pm_runtime_put(dd->dev);
-
      if (req->base.complete)
          req->base.complete(&req->base, err);

@@ -1239,6 +1229,7 @@ static int omap_sham_cra_init_alg(struct
crypto_tfm *tfm, const char *alg_base)
  {
      struct omap_sham_ctx *tctx = crypto_tfm_ctx(tfm);
      const char *alg_name = crypto_tfm_alg_name(tfm);
+    struct omap_sham_dev *dd;

      /* Allocate a fallback and abort if it failed. */
      tctx->fallback = crypto_alloc_shash(alg_name, 0,
@@ -1266,6 +1257,13 @@ static int omap_sham_cra_init_alg(struct
crypto_tfm *tfm, const char *alg_base)

      }

+    spin_lock_bh(&sham.lock);
+    list_for_each_entry(dd, &sham.dev_list, list) {
+        break;
+    }
+    spin_unlock_bh(&sham.lock);
+
+    pm_runtime_get_sync(dd->dev);
      return 0;
  }

@@ -1307,6 +1305,7 @@ static int omap_sham_cra_sha512_init(struct
crypto_tfm *tfm)
  static void omap_sham_cra_exit(struct crypto_tfm *tfm)
  {
      struct omap_sham_ctx *tctx = crypto_tfm_ctx(tfm);
+    struct omap_sham_dev *dd;

      crypto_free_shash(tctx->fallback);
      tctx->fallback = NULL;
@@ -1315,6 +1314,14 @@ static void omap_sham_cra_exit(struct
crypto_tfm *tfm)
          struct omap_sham_hmac_ctx *bctx = tctx->base;
          crypto_free_shash(bctx->shash);
      }
+
+    spin_lock_bh(&sham.lock);
+    list_for_each_entry(dd, &sham.dev_list, list) {
+        break;
+    }
+    spin_unlock_bh(&sham.lock);
+
+    pm_runtime_get_sync(dd->dev);

May be put_?

  }

  static struct ahash_alg algs_sha1_md5[] = {




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