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. Signed-off-by: Joel A Fernandes <joelagnel@xxxxxx> --- v2 changes: Clarify usage of runtime PM a bit more in the commit logs. drivers/crypto/omap-aes.c | 23 +++++++++++++++++++---- 1 files changed, 19 insertions(+), 4 deletions(-) diff --git a/drivers/crypto/omap-aes.c b/drivers/crypto/omap-aes.c index 6aa425f..e6474eb 100644 --- a/drivers/crypto/omap-aes.c +++ b/drivers/crypto/omap-aes.c @@ -208,7 +208,6 @@ static int omap_aes_hw_init(struct omap_aes_dev *dd) * 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; @@ -636,7 +635,6 @@ static void omap_aes_finish_req(struct omap_aes_dev *dd, int err) pr_debug("err: %d\n", err); - pm_runtime_put_sync(dd->dev); dd->flags &= ~FLAGS_BUSY; req->base.complete(&req->base, err); @@ -837,8 +835,16 @@ 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 +852,16 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html