From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To: Dave Jiang <dave.jiang@intel.com>
Cc: <linux-cxl@vger.kernel.org>, <dan.j.williams@intel.com>,
<linuxarm@huawei.com>, <ira.weiny@intel.com>,
<vishal.l.verma@intel.com>, <alison.schofield@intel.com>
Subject: Re: [RFC PATCH 2/2] cxl: Add tprintk support for header log hex dump
Date: Wed, 18 Jan 2023 09:43:09 +0000 [thread overview]
Message-ID: <20230118094309.0000008c@Huawei.com> (raw)
In-Reply-To: <0907017b-a620-0089-8d10-b3dc92e145ed@intel.com>
On Tue, 17 Jan 2023 11:08:26 -0700
Dave Jiang <dave.jiang@intel.com> wrote:
> On 1/13/23 8:40 AM, Jonathan Cameron wrote:
> > May not make sense in general, but very helpful when writing multiple
> > header logging support.
> >
> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>
> The user logging software would be retrieving from the log data directly
> instead of parsing the trace output right? Will people visually inspect
> the formatted trace output? Useful for debugging?
Rather depends on the use case and rate of expected errors + if you are
trying to debug errors before your logging infrastructure is up.
Sure in production, likely these tracepoints would just get stored to a DB for later
querying. But in debug, I often just use the kernel parameter
to directly dump them in the main kernel log, or perf's own decoding of a trace.
The nearest equivalent to this is AER which does print the log.
https://elixir.bootlin.com/linux/v6.2-rc4/source/include/ras/ras_event.h#L337
though that uses __print_array so maybe that's a better choice.
Don't get the nice offsets though if we do that though...
I'm not fussed about this patch going upstream or not, it just makes testing
patch 1 a lot easier :)
Jonathan
>
> > ---
> > drivers/cxl/core/trace.h | 7 +++++--
> > 1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
> > index 20ca2fe2ca8e..64f6ad13529d 100644
> > --- a/drivers/cxl/core/trace.h
> > +++ b/drivers/cxl/core/trace.h
> > @@ -62,10 +62,13 @@ TRACE_EVENT(cxl_aer_uncorrectable_error,
> > */
> > memcpy(__entry->header_log, hl, CXL_HEADERLOG_SIZE);
> > ),
> > - TP_printk("%s: status: '%s' first_error: '%s'",
> > + TP_printk("%s: status: '%s' first_error: '%s' header_log: %s",
> > __get_str(dev_name),
> > show_uc_errs(__entry->status),
> > - show_uc_errs(__entry->first_error)
> > + show_uc_errs(__entry->first_error),
> > + __print_hex_dump("", DUMP_PREFIX_OFFSET, 32, 4,
> > + (char *)__entry->header_log,
> > + CXL_HEADERLOG_SIZE_U32, false)
> > )
> > );
> >
next prev parent reply other threads:[~2023-01-18 10:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-13 15:40 [RFC PATCH 0/2] CXL UE RAS Multiple Header Logging support Jonathan Cameron
2023-01-13 15:40 ` [RFC PATCH 1/2] cxl: RAS: Multiple header recording support Jonathan Cameron
2023-01-17 18:05 ` Dave Jiang
2023-01-13 15:40 ` [RFC PATCH 2/2] cxl: Add tprintk support for header log hex dump Jonathan Cameron
2023-01-17 18:08 ` Dave Jiang
2023-01-18 9:43 ` Jonathan Cameron [this message]
2023-01-18 15:19 ` Dave Jiang
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