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

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Message-ID: <20170815060823.3orsmfbruefqps57@linux.intel.com>
Date:   Tue, 15 Aug 2017 09:08:23 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Mimi Zohar <zohar@...ux.vnet.ibm.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, Aug 14, 2017 at 08:03:05AM -0400, Mimi Zohar wrote:
> 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

We can revisit this. I would take the simple route right now.

/Jarkko