damo v2.5.7 new features: temperature filtering and formatting

damo v2.5.7 is released on 2024-11-25. Two new major features on this version are temperature-based regions filtering and formatting.

Temperature

“Temperature” of each memory region represents relative access hotness of the region. It is calculated as weighted sum of size, access rate (a.k.a nr_accesses) and age of each region. By default, the weights for the three properties are 0, 100, and 100. Users can manually set it using --temperature_weights option.

Temperature-based regions filtering

This feature allows users filter regions of specific temperature range. For example, below shows the access pattern of a Java-based server workload’s access pattern in the temperature range to total size of regions of the range histogram visualization format (a.k.a temperature-sz-hist style).

$ sudo damo report access --style temperature-sz-hist
<temperature> <total size>
[-571000000000, -509579999000) 108.000 KiB |*                   |
[-509579999000, -448159998000) 4.000 KiB   |*                   |
[-448159998000, -386739997000) 20.000 KiB  |*                   |
[-386739997000, -325319996000) 0 B         |                    |
[-325319996000, -263899995000) 84.000 KiB  |*                   |
[-263899995000, -202479994000) 0 B         |                    |
[-202479994000, -141059993000) 3.271 GiB   |**                  |
[-141059993000, -79639992000)  2.953 GiB   |**                  |
[-79639992000, -18219991000)   10.412 GiB  |******              |
[-18219991000, 43200010000)    40.116 GiB  |********************|
[43200010000, 104620011000)    84.000 KiB  |*                   |
total size: 56.752 GiB

From the result, we can know there are warm memory regions of about 40 GiB total size, and hot memory region of 84 KiB total size. Now users would want to know further what access pattern is inside the 40 GiB regions. Users can use the temperature filter feature for the purpose, like below.

$ sudo damo report access --temperature -18219991000 43200010000 --style temperature-sz-hist
<temperature> <total size>
[-18,000,000,000, -11,879,999,000) 3.874 GiB   |****                |
[-11,879,999,000, -5,759,998,000)  11.585 GiB  |**********          |
[-5,759,998,000, 360,003,000)      23.979 GiB  |********************|
[360,003,000, 6,480,004,000)       693.363 MiB |*                   |
[6,480,004,000, 12,600,005,000)    40.000 KiB  |*                   |
[12,600,005,000, 18,720,006,000)   100.000 KiB |*                   |
[18,720,006,000, 24,840,007,000)   0 B         |                    |
[24,840,007,000, 30,960,008,000)   8.000 KiB   |*                   |
[30,960,008,000, 37,080,009,000)   28.000 KiB  |*                   |
[37,080,009,000, 43,200,010,000)   12.000 KiB  |*                   |
[43,200,010,000, 49,320,011,000)   84.000 KiB  |*                   |
total size: 40.116 GiB

Note that damo report access supports more types of region filters. Refer to the usage document for more details.

Regions formatting with temperature

The filtered histogram shows more details. In some cases, users may want to further know not only the total size but every detail of each region, including address, size, access rate, age, and the calculated temperature. The size and address would be specifically interesting if the user is interested in some contiguity-related optimizations like THP.

damo report access allows users formatting the output in a flexible way. From damo v2.5.7, the command supports showing temperature of each region. For example, users can show each region’s start address, size, access rate, age, and the temperature like below.

$ sudo damo report access --format_region "<start address> <size> <access rate> <age> <temperature>"
16.219 GiB   93.281 MiB  0 %   22 s -2,200,000,000
16.310 GiB   32.000 KiB  100 % 1 m 36 s 9,600,010,000
16.310 GiB   28.000 KiB  0 %   2 s -,200,000,000
16.310 GiB   32.000 KiB  40 %  4 s 400,004,000
16.310 GiB   84.000 KiB  10 %  0 ns 1,000
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