From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
To: Mathieu Poirier <mathieu.poirier@linaro.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Cc: linux-doc@vger.kernel.org, zhang.chunyan@linaro.org,
mike.leach@arm.com, tor@ti.com, al.grant@arm.com, rabin@rab.in,
Mathieu Poirier <mathieu.poirier@linaro.org>
Subject: Re: [PATCH V8 16/23] coresight: etb10: implementing AUX API
Date: Tue, 26 Jan 2016 17:53:56 +0200 [thread overview]
Message-ID: <8760yg72wb.fsf@ashishki-desk.ger.corp.intel.com> (raw)
In-Reply-To: <1452807977-8069-17-git-send-email-mathieu.poirier@linaro.org>
Mathieu Poirier <mathieu.poirier@linaro.org> writes:
> Adding an ETB10 specific AUX area operations to be used
> by the perf framework when events are initialised.
>
> Part of this operation involves modeling the mmap'ed area
> based on the specific ways a sink buffer gathers information.
I don't mind being CC'd on the rest of the patches too, btw. :)
> +static unsigned long etb_reset_buffer(struct coresight_device *csdev,
> + struct perf_output_handle *handle,
> + void *sink_config, bool *lost)
> +{
> + unsigned long size = 0;
> + struct cs_buffers *buf = sink_config;
> +
> + if (buf) {
> + /*
> + * In snapshot mode ->data_size holds the new address of the
> + * ring buffer's head. The size itself is the whole address
> + * range since we want the latest information.
> + */
> + if (buf->snapshot)
> + handle->head = local_xchg(&buf->data_size,
> + buf->nr_pages << PAGE_SHIFT);
> +
> + /*
> + * Tell the tracer PMU how much we got in this run and if
> + * something went wrong along the way. Nobody else can use
> + * this cs_buffers instance until we are done. As such
> + * resetting parameters here and squaring off with the ring
> + * buffer API in the tracer PMU is fine.
> + */
> + *lost = local_xchg(&buf->lost, 0);
This is a thin ice, you can't really make assumptions about bool's
storage size or even type, afaict.
> + size = local_xchg(&buf->data_size, 0);
> + }
> +
> + return size;
> +}
> +
> +static void etb_update_buffer(struct coresight_device *csdev,
> + struct perf_output_handle *handle,
> + void *sink_config)
> +{
> + int i, cur;
> + u8 *buf_ptr;
> + u32 read_ptr, write_ptr, capacity;
> + u32 status, read_data, to_read;
> + unsigned long flags, offset;
> + struct cs_buffers *buf = sink_config;
> + struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
> +
> + if (!buf)
> + return;
> +
> + capacity = drvdata->buffer_depth * ETB_FRAME_SIZE_WORDS;
> +
> + spin_lock_irqsave(&drvdata->spinlock, flags);
This spinlock seems to be held over the entire readout operation,
however, I can't find clear rules wrt what structures etc are serialized
on it. Instead, the comment says "only one at a time pls". Same for
etm's big drvdata spinlock.
Regards,
--
Alex
next prev parent reply other threads:[~2016-01-26 15:54 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-14 21:45 [PATCH V8 00/23] Coresight integration with perf Mathieu Poirier
2016-01-14 21:45 ` [PATCH V8 01/23] coresight: associating path with session rather than tracer Mathieu Poirier
2016-01-14 21:45 ` [PATCH V8 02/23] coresight: add API to get sink from path Mathieu Poirier
2016-01-14 21:45 ` [PATCH V8 03/23] coresight: moving PM runtime operations to core framework Mathieu Poirier
2016-01-14 21:45 ` [PATCH V8 04/23] coresight: etm3x: moving etm_readl/writel to header file Mathieu Poirier
2016-01-14 21:45 ` [PATCH V8 05/23] coresight: etm3x: moving sysFS entries to dedicated file Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 06/23] coresight: etm3x: unlocking tracers in default arch init Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 07/23] coresight: etm3x: splitting struct etm_drvdata Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 08/23] coresight: etm3x: adding operation mode for etm_enable() Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 09/23] coresight: etm3x: set progbit to stop trace collection Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 10/23] coresight: etm3x: changing default trace configuration Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 11/23] coresight: etm3x: consolidating initial config Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 12/23] coresight: etm3x: implementing user/kernel mode tracing Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 13/23] coresight: etm3x: implementing perf_enable/disable() API Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 14/23] coresight: etb10: moving to local atomic operations Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 15/23] coresight: etb10: adding operation mode for sink->enable() Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 16/23] coresight: etb10: implementing AUX API Mathieu Poirier
2016-01-26 15:53 ` Alexander Shishkin [this message]
2016-01-27 20:55 ` Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 17/23] coresight: updating documentation to reflect integration with perf Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 18/23] coresight: etm-perf: new PMU driver for ETM tracers Mathieu Poirier
2016-01-26 15:27 ` Alexander Shishkin
2016-01-27 18:33 ` Mathieu Poirier
2016-01-28 15:42 ` Alexander Shishkin
2016-01-28 21:12 ` Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 19/23] coresight: introducing a global trace ID function Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 20/23] perf tools: making function set_max_cpu_num() non static Mathieu Poirier
2016-01-25 20:46 ` Mathieu Poirier
2016-01-25 21:12 ` Arnaldo Carvalho de Melo
2016-01-25 21:29 ` Arnaldo Carvalho de Melo
2016-01-26 17:08 ` Mathieu Poirier
2016-01-26 18:51 ` Arnaldo Carvalho de Melo
2016-01-27 16:24 ` Mathieu Poirier
2016-02-03 10:15 ` [tip:perf/core] perf cpumap: Auto initialize cpu__max_{node,cpu} tip-bot for Arnaldo Carvalho de Melo
2016-01-14 21:46 ` [PATCH V8 21/23] perf tools: adding perf_evlist to *info_priv_size() Mathieu Poirier
2016-01-25 20:48 ` Mathieu Poirier
2016-01-25 21:08 ` Arnaldo Carvalho de Melo
2016-01-26 14:27 ` Adrian Hunter
2016-01-26 14:33 ` Arnaldo Carvalho de Melo
2016-01-29 10:14 ` Adrian Hunter
2016-02-03 10:17 ` [tip:perf/core] perf auxtrace: Add perf_evlist pointer " tip-bot for Mathieu Poirier
2016-01-14 21:46 ` [PATCH V8 22/23] perf tools: making coresight PMU listable Mathieu Poirier
2016-01-25 20:49 ` Mathieu Poirier
2016-01-25 21:10 ` Arnaldo Carvalho de Melo
2016-01-29 10:24 ` Adrian Hunter
2016-01-14 21:46 ` [PATCH V8 23/23] perf tools: adding coresight etm PMU record capabilities Mathieu Poirier
2016-01-25 20:51 ` Mathieu Poirier
2016-01-25 21:10 ` Arnaldo Carvalho de Melo
2016-01-29 10:34 ` Adrian Hunter
2016-01-29 17:37 ` Mathieu Poirier
2016-01-29 21:12 ` Arnaldo Carvalho de Melo
2016-01-29 22:24 ` Mathieu Poirier
2016-02-02 16:20 ` Mathieu Poirier
2016-02-02 16:41 ` Arnaldo Carvalho de Melo
2016-02-03 16:11 ` Mathieu Poirier
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