Messages in this thread | | | Subject | Re: [PATCH v9 08/22] tracing: Add 'hist' event trigger command | From | Tom Zanussi <> | Date | Tue, 21 Jul 2015 09:17:06 -0500 |
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Hi Masami,
On Mon, 2015-07-20 at 22:37 +0900, Masami Hiramatsu wrote: > Hi Tom, > > On 2015/07/17 2:22, Tom Zanussi wrote: > > > @@ -3782,6 +3785,32 @@ static const char readme_msg[] = > > "\t To remove a trigger with a count:\n" > > "\t echo '!<trigger>:0 > <system>/<event>/trigger\n" > > "\t Filters can be ignored when removing a trigger.\n" > > +#ifdef CONFIG_HIST_TRIGGERS > > + " hist trigger\t- If set, event hits are aggregated into a hash table\n" > > + "\t Format: hist:keys=<field1>\n" > > + "\t [:size=#entries]\n" > > + "\t [if <filter>]\n\n" > > + "\t When a matching event is hit, an entry is added to a hash\n" > > + "\t table using the key named. Keys correspond to fields in the\n" > > + "\t event's format description. On an event hit, the value of a\n" > > + "\t sum called 'hitcount' is incremented, which is simply a count\n" > > + "\t of event hits. Keys can be any field.\n\n" > > + "\t Reading the 'hist' file for the event will dump the hash\n" > > + "\t table in its entirety to stdout. Each printed hash table\n" > > + "\t entry is a simple list of the keys and values comprising the\n" > > + "\t entry; keys are printed first and are delineated by curly\n" > > + "\t braces, and are followed by the set of value fields for the\n" > > + "\t entry. Numeric fields are displayed as base-10 integers.\n" > > + "\t By default, the size of the hash table is 2048 entries. The\n" > > + "\t 'size' param can be used to specify more or fewer than that.\n" > > + "\t The units are in terms of hashtable entries - if a run uses\n" > > + "\t more entries than specified, the results will show the number\n" > > + "\t of 'drops', the number of hits that were ignored. The size\n" > > + "\t should be a power of 2 between 128 and 131072 (any non-\n" > > + "\t power-of-2 number specified will be rounded up).\n\n" > > + "\t The entries are sorted by 'hitcount' and the sort order is\n" > > + "\t 'ascending'.\n\n" > > > Hmm, this seems too much about implementation of histogram. Could you shorten this > to be a half ? >
OK, I'll try to cut it down to just usage essentials.
Tom
> > Thank you, > >
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