Re: High CPU load with pcscd and Kerkey security Module

Oliver Graute <[email protected]> Mon, 21 Nov 2016 11:47:09 +0100
Newsgroups gmane.comp.lib.muscle
Message-ID <CA+KjHfa4R_ZbS5AKisgd3nTH-1bo+ow+wQ8nky-r_rajmhtfWA@mail.gmail.com>
On Fri, Nov 18, 2016 at 1:37 PM, Ludovic Rousseau
<[email protected]> wrote:
> 2016-11-18 10:24 GMT+01:00 Oliver Graute <[email protected]>:
>> On Wed, Nov 16, 2016 at 2:31 PM, Ludovic Rousseau
>> <[email protected]> wrote:

> I could not find a real problem in your logs.
>
> Your PC/SC application is NOT efficient and you could gain of lot of CPU cycle.
> - replace SCardStatus() busy loop by SCardGetStatusChange()
> - do not use SCardBeginTransaction()/SCardEndTransaction() with no
> APDU exchange in between. It is useless, unless I missed something.


Many thanks for your analysis and your comment.
My pcscd-spy debugging leads to similar results

Results sorted by total execution time
total time: 597.958052 sec
42.015016 sec (308 calls)  7.03% SCardTransmit
9.974089 sec (1687 calls)  1.67% SCardStatus

> Are you the author of the PC/SC application running on your board?

No, we are using a custom libpkk11 PKCS11# Host middleware on
top of pcscd, unfortunately this lib is closed source for me. So I need to
contact the Libkkp11 team  (ST Microsystem) to investigate this further.

Best Regards,

Oliver