From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Jason Gunthorpe <jgg@ziepe.ca>, Alexander.Steffen@infineon.com
Cc: pmenzel@molgen.mpg.de, linux-integrity@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [Regression 4.15-rc2] New messages `tpm tpm0: A TPM error (2314) occurred continue selftest`
Date: Fri, 08 Dec 2017 11:17:51 -0500 [thread overview]
Message-ID: <1512749871.4364.9.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <20171208155641.GA2883@ziepe.ca>
On Fri, 2017-12-08 at 08:56 -0700, Jason Gunthorpe wrote:
> On Fri, Dec 08, 2017 at 12:14:04PM +0000, Alexander.Steffen@infineon.com wrote:
>
> > Is it really that ugly? I still need delay_msec to increase the
> > delay each round. I can see the benefit of your suggestion when it
> > is important to get the timing exactly right (and also account for
> > time spent elsewhere, when our code might not be executing). But in
> > this case having delays that are approximately right (or longer than
> > intended) is sufficient.
>
> For timeouts like this we really need to be above the TPM specified
> delay in all cases, even if usleep_range selected something
> smaller/larger.. The only way to do that is with an absolute timeout..
>
>
> > Anyway, from the log messages it is clear that tpm_msleep got called
> > seven times with delays of 20/40/80/160/320/640/1280ms. But still
> > all timestamps lie within the same second. How can this be with a
> > cumulated delay of ~2.5s?
>
> Yes, that does seem to be the bug, our sleep function doesn't work
> aynmore for some reason :|
>
> > Also, I've just noticed that despite the name tpm_msleep calls
> > usleep_range, not msleep. Can this have an influence? Should
> > tpm_msleep call msleep for longer delays, as suggested by
> > Documentation/timers/timers-howto.txt?
>
> This change was introduced recently and is probably the source of this
> regression.
msleep() waited a lot longer than the requested time, causing long
delays. Using usleep_range() still waits more than the requested
time, but less than msleep().
static inline void tpm_msleep(unsigned int delay_msec)
{
usleep_range((delay_msec * 1000) - TPM_TIMEOUT_RANGE_US,
delay_msec * 1000);
};
Other TPM performance improvements have not yet been upstreamed.
Mimi
prev parent reply other threads:[~2017-12-08 16:18 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-06 12:34 [Regression 4.15-rc2] New messages `tpm tpm0: A TPM error (2314) occurred continue selftest` Paul Menzel
2017-12-06 16:40 ` Jason Gunthorpe
2017-12-07 15:56 ` Alexander.Steffen
2017-12-07 18:37 ` Jason Gunthorpe
2017-12-08 12:14 ` Alexander.Steffen
2017-12-08 15:56 ` Jason Gunthorpe
2017-12-08 16:07 ` Paul Menzel
2017-12-08 16:18 ` Jason Gunthorpe
2017-12-11 12:54 ` Paul Menzel
2017-12-11 16:08 ` Alexander.Steffen
2017-12-14 10:33 ` Paul Menzel
2017-12-14 12:20 ` Alexander.Steffen
2017-12-14 14:15 ` Mario.Limonciello
2017-12-14 16:12 ` Alexander.Steffen
2017-12-14 19:43 ` Mario.Limonciello
2017-12-15 11:54 ` Paul Menzel
2017-12-15 14:39 ` Mario.Limonciello
2017-12-15 15:10 ` Paul Menzel
2017-12-15 15:24 ` Mario.Limonciello
2017-12-15 15:38 ` Paul Menzel
2017-12-15 14:54 ` Alexander.Steffen
2017-12-15 15:26 ` Paul Menzel
2017-12-21 13:36 ` Mimi Zohar
2017-12-22 14:00 ` Alexander.Steffen
2017-12-22 14:08 ` Paul Menzel
2017-12-08 16:17 ` Mimi Zohar [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1512749871.4364.9.camel@linux.vnet.ibm.com \
--to=zohar@linux.vnet.ibm.com \
--cc=Alexander.Steffen@infineon.com \
--cc=jgg@ziepe.ca \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pmenzel@molgen.mpg.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).