Messages in this thread | | | Date | Tue, 6 Jul 2021 20:50:39 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH v2] tracing: Add linear buckets to histogram logic |
| |
On Tue, 6 Jul 2021 16:20:07 -0700 Namhyung Kim <namhyung@kernel.org> wrote:
> > { bytes_req: ~ 1400-1499 } hitcount: 30 > > { bytes_req: ~ 2000-2099 } hitcount: 6 > > { bytes_req: ~ 4000-4099 } hitcount: 2168 > > { bytes_req: ~ 5000-5099 } hitcount: 6 > > For consistency with the log2 histogram, I'd like to see > > { bytes_req: ~ 100 } hitcount: 3149 > { bytes_req: ~ 200 } hitcount: 1468 > { bytes_req: ~ 300 } hitcount: 39 > ... > > Or, if you really care about the value range > > { bytes_req: 0 ~ 99 } hitcount: 3149 > { bytes_req: 100 ~ 199 } hitcount: 1468 > { bytes_req: 200 ~ 299 } hitcount: 39
(Let the bike-shedding begin! ;-)
I actually dislike the log2 notation. For example, I just ran it with this:
># echo 'hist:keys=bytes_req.log2:sort=bytes_req' > events/kmem/kmalloc/trigger ># cat events/kmem/kmalloc/hist # event histogram # # trigger info: hist:keys=bytes_req.log2:vals=hitcount:sort=bytes_req.log2:size=2048 [active] #
{ bytes_req: ~ 2^5 } hitcount: 8 { bytes_req: ~ 2^6 } hitcount: 2 { bytes_req: ~ 2^7 } hitcount: 4 { bytes_req: ~ 2^8 } hitcount: 2 { bytes_req: ~ 2^9 } hitcount: 2 { bytes_req: ~ 2^10 } hitcount: 3
Totals: Hits: 21 Entries: 6 Dropped: 0
And I don't know if that first entry is: 2^4 - 2^5 or if it is 2^5 - 2^6.
And to me '~' means "approximately", but I also took it as "not exactly". I used it as:
{ bytes_req: ~ 1400-1499 } hitcount: 30
To mean, it's "approximately somewhere between 1400 and 1499" so, I kept the "~".
Now for your suggestions:
> { bytes_req: ~ 100 } hitcount: 3149 > { bytes_req: ~ 200 } hitcount: 1468 > { bytes_req: ~ 300 } hitcount: 39
Suffers the same fate as I dislike in log2. Is " ~ 100" 0-100 or 100-200?
> { bytes_req: 0 ~ 99 } hitcount: 3149 > { bytes_req: 100 ~ 199 } hitcount: 1468 > { bytes_req: 200 ~ 299 } hitcount: 39
I feel is farther from log2 than my version. Stating that "~" means approximation, what does "0 ~ 99" really mean?
So far I prefer my original version.
BTW, we are also working on a user space parser for this, thus the output format of all hist logic is going to be a user space API (if it hasn't already become one.)
So we do need to get this correct for the long haul.
-- Steve
| |