* Re: [PATCH] tools:perf:scripts:python:mem-phys-addr fix performance
2023-01-09 9:33 [PATCH] tools:perf:scripts:python:mem-phys-addr fix performance Alexander Pantyukhin
@ 2023-01-09 20:44 ` Alexander Pantyukhin
0 siblings, 0 replies; 2+ messages in thread
From: Alexander Pantyukhin @ 2023-01-09 20:44 UTC (permalink / raw)
To: mark.rutland
Cc: peterz, mingo, acme, alexander.shishkin, jolsa, namhyung,
linux-perf-users, linux-kernel
Hi!
There are some things which I would like to discuss there.
1) I found that if there is for example the following system_ram:
system_ram = [int('00000000', 16) , int('0000ffff', 16)]
and the func
def is_system_ram(phys_addr):
#/proc/iomem is sorted
position = bisect.bisect(system_ram, phys_addr)
if position % 2 == 0:
return False
return True
The value:
is_system_ram(int('0000ffff', 16)) is False.
It seems to be a mistake. This value is the end of the range and it
should be a True.
(There is another check on the 88 line: if int(m[0], 16) <= phys_addr
<= int(m[1], 16)
where both ranges are included in the check.)
2) The script reads the whole file when parse_iomem()
and uses this information for pmem and system_ram. What if to store
whole info about addresses
for all memory types?
In This case it's possible to store the data structure like the
following example:
/proc/iomem
00000000-0000ffff : reserved
00010000-0009f3ff : System RAM
Result: [(00000000, 'reserved'), (0000ffff, 'reserved'), (00010000,
'System RAM'), (0009f3ff, 'System RAM')....]
This case the searching would be O(log(n)) for all types not just for
"System RAM" and "Persistent Memory".
But the behavior of the script would be changed: the current version
re-read the file and scan the fresh data
when neither "System RAM" nor "Persistent Memory". But the suggested
fix requires to call parse_iomem() when
fresh data is required.
If these changes are approved, I would like to fix it.
Best, Alex.
пн, 9 янв. 2023 г. в 13:33, Alexander Pantyukhin <apantykhin@gmail.com>:
>
> Avoid double strip() calls for getting memory type.
>
> Signed-off-by: Alexander Pantyukhin <apantykhin@gmail.com>
> ---
> tools/perf/scripts/python/mem-phys-addr.py | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/scripts/python/mem-phys-addr.py b/tools/perf/scripts/python/mem-phys-addr.py
> index 1f332e72b9b0..f267d8382eda 100644
> --- a/tools/perf/scripts/python/mem-phys-addr.py
> +++ b/tools/perf/scripts/python/mem-phys-addr.py
> @@ -8,7 +8,6 @@ from __future__ import print_function
>
> import os
> import sys
> -import struct
> import re
> import bisect
> import collections
> @@ -30,12 +29,14 @@ event_name = None
> def parse_iomem():
> global f
> f = open('/proc/iomem', 'r')
> - for i, j in enumerate(f):
> + for _, j in enumerate(f):
> m = re.split('-|:',j,2)
> - if m[2].strip() == 'System RAM':
> + memory_type = m[2].strip()
> +
> + if memory_type == 'System RAM':
> system_ram.append(int(m[0], 16))
> system_ram.append(int(m[1], 16))
> - if m[2].strip() == 'Persistent Memory':
> + elif memory_type == 'Persistent Memory':
> pmem.append(int(m[0], 16))
> pmem.append(int(m[1], 16))
>
> @@ -75,6 +76,7 @@ def is_persistent_mem(phys_addr):
> def find_memory_type(phys_addr):
> if phys_addr == 0:
> return "N/A"
> +
> if is_system_ram(phys_addr):
> return "System RAM"
>
> --
> 2.25.1
>
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