On 3/4/21 2:19 PM, Mike Leach wrote:
Hi Suzuki,
On Thu, 4 Mar 2021 at 12:13, Suzuki K Poulose <suzuki.poulose@xxxxxxx> wrote:
On 1/28/21 5:09 PM, Mike Leach wrote:
Loaded coresight configurations are registered in the cs_etm\cs_config sub
directory. This extends the etm-perf code to handle these registrations,
and the cs_syscfg driver to perform the registration on load.
Signed-off-by: Mike Leach <mike.leach@xxxxxxxxxx>
---
.../hwtracing/coresight/coresight-config.h | 5 +-
.../hwtracing/coresight/coresight-etm-perf.c | 164 +++++++++++++++---
.../hwtracing/coresight/coresight-etm-perf.h | 8 +
.../hwtracing/coresight/coresight-syscfg.c | 13 +-
4 files changed, 166 insertions(+), 24 deletions(-)
+static ssize_t etm_perf_cscfg_event_show(struct device *dev,
+ struct device_attribute *dattr,
+ char *buf)
+{
+ struct dev_ext_attribute *ea;
+
+ ea = container_of(dattr, struct dev_ext_attribute, attr);
+ return scnprintf(buf, PAGE_SIZE, "%s\n", (const char *)(ea->var));
+}
"configid=0x%lx", (unsigned long)ea->var ?
ea->var _is_ "configid=0x%lx" due to the way perf handles the events
sub-dir entries.
This must be combined with the suggestion below.
+
+static int etm_perf_add_cscfg_event(struct device *dev, struct cscfg_config_desc *cs_cfg)
+{
+ struct dev_ext_attribute *ea;
+ unsigned long hash;
+ int ret;
+ struct device *pmu_dev = etm_pmu.dev;
+
+ ea = devm_kzalloc(dev, sizeof(*ea), GFP_KERNEL);
+ if (!ea)
+ return -ENOMEM;
+
+ hash = (unsigned long)cs_cfg->id_ea->var;
+
+ sysfs_attr_init(&ea->attr.attr);
+ ea->attr.attr.name = devm_kstrdup(dev, cs_cfg->name, GFP_KERNEL);
+ if (!ea->attr.attr.name)
+ return -ENOMEM;
+
+ /*
+ * attribute value is "configid=<hash>".
+ * this will be what perf evaluates when the config name is used
+ * on the command line.
+ */
+ ea->var = devm_kzalloc(dev, CSCFG_EVENT_STR_SIZE, GFP_KERNEL);
+ if (!ea->var)
+ return -ENOMEM;
Could we drop this string and use the "hash" instead ?
No. My understanding is that we have added an events directory to
cs_etm, and add the configurations in there:-
cs_etm/events/autofdo
Now the contents of autofdo are "configid=0x<hash-value>" - where
hash-value is the hash of "autofdo".
On the perf command line:-
perf record -e cs_etm/autofdo/ .....
will result in perf parsing autofdo, looking in the events dir for
cs_etm, seeing the configid=-string, and parsing that to assign to
configid attribute - which we have allocated to config2:63:32 - this
will then appear as a value in the perf_event and we can load the
configuration when starting up the event on the ETM etc.
Sorry, I was not explicit in my comments. You could drop the string and
have ea->var = hash. And the _show() could simply do
"configid=0x%lx" , hash
as mentioned above.
That would avoid another string allocation, with the same interface.
Suzuki
