linux-kernel - Re: Re: [tpmdd-devel] [PATCH] tpm: improve tpm_tis send() performance by ignoring burstcount

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Message-Id: <1502712185.6179.20.camel@linux.vnet.ibm.com>
Date:   Mon, 14 Aug 2017 08:03:05 -0400
From:   Mimi Zohar <zohar@...ux.vnet.ibm.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     Peter Huewe <PeterHuewe@....de>,
        Ken Goldman <kgold@...ux.vnet.ibm.com>,
        linux-ima-devel@...ts.sourceforge.net,
        linux-security-module@...r.kernel.org,
        tpmdd-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org
Subject: Re: Re: [tpmdd-devel] [PATCH] tpm: improve tpm_tis send()
 performance by ignoring burstcount

On Mon, 2017-08-14 at 13:56 +0300, Jarkko Sakkinen wrote:

> > > > I would like to see tpm_msleep() wrapper to replace current msleep()
> > > > usage across the subsystem before considering this. I.e. wrapper that
> > > > internally uses usleep_range(). This way we can mechanically convert
> > > > everything to a more low latency option.
> > > 
> > > Fine.  I assume you meant tpm_sleep(), not tpm_msleep().
> > 
> > I think it would sense to have a function that takes msecs because msecs
> > are mostly used everywhere in the subsystem. This way we don't have to
> > change any of the existing constants.

For now converting from msleep() to tpm_msleep() will be straight
forward.  Internally we would just use usleep_range().

Going forward, my concern is that even 1 msec might be too long for
some of these sleeps.

Mimi