Performance/MemShrink/about:memory - Revision history

Nnethercote: Replaced content with "This page's contents have moved to [https://developer.mozilla.org/en-US/docs/Mozilla/Performance/about:memory MDN]"

2014-10-21T04:56:19Z

Replaced content with "This page's contents have moved to [https://developer.mozilla.org/en-US/docs/Mozilla/Performance/about:memory MDN]"

← Older revision		Revision as of 04:56, 21 October 2014
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	~~about:memory is a special~~ page that lets you view, save, load, and diff detailed measurements of Firefox's memory usage. It also lets you do other memory-related operations like trigger GC and CC, dump GC & CC logs, and dump DMD reports.		This page's contents have moved to [https://developer.mozilla.org/en-US/docs/Mozilla/Performance/about:memory MDN]

	~~Type "about:memory" into the browser's address bar to view it.~~

	~~== Things that make your life easier ==~~

	~~Almost everything you see in about:memory has an explanatory tool-tip. Hover over any button to see a description of what it does. Hover over any measurement to see a description of what it means.~~

	~~You can copy and paste part or all of about:memory~~'s contents ~~into any text buffer. This is much easier than taking screenshots.~~

	~~Memory reports are saved~~ to ~~file as gzipped JSON, and by default are given a .json.gz extension. These files can be loaded as is, but they can also be loaded after unzipping.~~

	~~Memory reports can be loaded automatically when about:memory is loaded by appending a <tt>file</tt> query string, for example:~~

	~~about~~:~~memory?file=~~/~~home~~/~~username/reports.json.gz~~

	~~This is most useful when loading memory reports files obtained from a Firefox OS device.~~

	~~== Measurements ==~~

	~~=== Basics ===~~

	~~Most measurements use bytes as their unit, but some are counts or percentages.~~

	~~Most measurements are presented within trees. For example:~~

	~~585 (100.0%) -- preference-service~~
	~~└──585 (100.0%) -- referent~~
	~~├──493 (84.27%) ── strong~~
	~~└───92 (15~~.~~73%) -- weak~~
	~~├──92 (15~~.~~73%) ── alive~~
	~~└───0 (00.00%) ── dead~~

	~~Leaf nodes represent actual measurements; the value of each internal node is the sum of all its children.~~

	The use of trees allows measurements to be broken down into further categories, sub-categories, sub-sub-categories, etc., to arbitrary depth, as needed. All the measurements within a single tree are non-overlapping.

	~~Tree paths can be written using '~~/~~' as a separator. For example, "preference/referent/weak/dead" represents the path to the final leaf node in the example tree above.~~

	~~Sub~~-trees can be collapsed or expanded by clicking on them. If you find any particular tree overwhelming, it can be helpful to collapse all the sub-trees immediately below the root, and then gradually expand the sub-trees of interest.

	~~=== Sections ===~~

	~~Memory reports are displayed on a per-process basis, with one process per section. Within each process's measurements, there are the following two subsections.~~

	* "Explicit Allocations". This tree measures all the memory allocated via explicit calls to heap allocation functions (such as <tt>malloc</~~tt> and <tt>new<~~/~~tt>) and to non-heap allocations functions (such as <tt>mmap<~~/~~tt> and <tt>VirtualAlloc<~~/~~tt>).~~
	* "Other Measurements". This collection of trees includes many that cross-cut the measurements in the "Explicit Allocations" tree. For example, in "Explicit Allocations" all DOM and layout measurements are segmented by window, but in "Other Measurements" those measurements are aggregated into totals for the whole browser.

	On Firefox OS, there is also a "System" section which contains whole-device measurements obtained from the operating system. Among other things, this section is useful for understanding exactly how the whole device's memory is being used.

	~~=== Notable measurements ===~~

	~~The exact set of measurements shown in~~ about:memory ~~changes frequently. However, here are some notable ones.~~

	* "explicit". This value is at the root of the tree in the "Explicit Allocations" section. As mentioned above, this represents all the memory allocated via explicit calls to allocation functions.
	* "resident". Physical memory usage. If you want a single measurement to summarize memory usage, this is probably the best one.
	* "vsize". Virtual memory usage.
	* "heap-unclassified". This is heap-allocated memory that is not measured by any memory reporter. This is typically 10--15% of "explicit". If it gets higher, it indicates that additional memory reporters should be added. [[Performance/MemShrink/DMD\|DMD]~~] can be used to determine where these memory reporters should be added.~~

Nnethercote: /* Notable measurements */

2014-10-17T04:59:13Z

Notable measurements

← Older revision		Revision as of 04:59, 17 October 2014
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	* "resident". Physical memory usage. If you want a single measurement to summarize memory usage, this is probably the best one.		* "resident". Physical memory usage. If you want a single measurement to summarize memory usage, this is probably the best one.
	* "vsize". Virtual memory usage.		* "vsize". Virtual memory usage.
	* "heap-unclassified". This is heap-allocated memory that is not measured by any memory reporter. This is typically 10--15% of "explicit". If it gets higher, it indicates that additional memory reporters should be added. [[Performance/MemShrink/DMD]] can be used to determine where these memory reporters should be added.		* "heap-unclassified". This is heap-allocated memory that is not measured by any memory reporter. This is typically 10--15% of "explicit". If it gets higher, it indicates that additional memory reporters should be added. [[Performance/MemShrink/DMD\|DMD]] can be used to determine where these memory reporters should be added.

Nnethercote at 01:19, 26 May 2014

2014-05-26T01:19:04Z

← Older revision		Revision as of 01:19, 26 May 2014
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	You can copy and paste part or all of about:memory's contents into any text buffer. This is much easier than taking screenshots.		You can copy and paste part or all of about:memory's contents into any text buffer. This is much easier than taking screenshots.

	Memory reports are saved to file as gzipped JSON, and ~~so have~~ a .json.gz extension. These files can be loaded as is, but they can also be loaded after unzipping.		Memory reports are saved to file as gzipped JSON, and by default are given a .json.gz extension. These files can be loaded as is, but they can also be loaded after unzipping.

			Memory reports can be loaded automatically when about:memory is loaded by appending a <tt>file</tt> query string, for example:

			about:memory?file=/home/username/reports.json.gz

			This is most useful when loading memory reports files obtained from a Firefox OS device.

	== Measurements ==		== Measurements ==
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	└───0 (00.00%) ── dead		└───0 (00.00%) ── dead

	~~This~~ allows measurements to be broken down into further categories, sub-categories, sub-sub-categories, etc., as needed~~. The value of each internal node is the sum of all its children~~. All the measurements within a single tree are non-overlapping.		Leaf nodes represent actual measurements; the value of each internal node is the sum of all its children.

			The use of trees allows measurements to be broken down into further categories, sub-categories, sub-sub-categories, etc., to arbitrary depth, as needed. All the measurements within a single tree are non-overlapping.

			Tree paths can be written using '/' as a separator. For example, "preference/referent/weak/dead" represents the path to the final leaf node in the example tree above.

	~~Tree paths~~ can be ~~written using '/' as a separator~~. ~~For example~~, ~~"preference/referent/weak/alive" indicates a one path~~ to ~~a leaf node in~~ the ~~above tree~~.		Sub-trees can be collapsed or expanded by clicking on them. If you find any particular tree overwhelming, it can be helpful to collapse all the sub-trees immediately below the root, and then gradually expand the sub-trees of interest.

	=== Sections ===		=== Sections ===

	Memory reports are displayed on a per-process basis. Within each process's measurements, there are two ~~sections~~.		Memory reports are displayed on a per-process basis, with one process per section. Within each process's measurements, there are the following two subsections.

	* "Explicit Allocations". This tree measures all the memory allocated via explicit calls to heap allocation functions (such as <tt>malloc</tt> and <tt>new</tt>) and to non-heap allocations functions (such as <tt>mmap</tt> and <tt>VirtualAlloc</tt>).		* "Explicit Allocations". This tree measures all the memory allocated via explicit calls to heap allocation functions (such as <tt>malloc</tt> and <tt>new</tt>) and to non-heap allocations functions (such as <tt>mmap</tt> and <tt>VirtualAlloc</tt>).
	* "Other Measurements". This collection of trees includes many that cross-cut the measurements in the "Explicit Allocations" tree. For example, in "Explicit Allocations" all DOM and layout measurements are segmented by window, but in "Other Measurements" those measurements are aggregated into totals for the whole browser.		* "Other Measurements". This collection of trees includes many that cross-cut the measurements in the "Explicit Allocations" tree. For example, in "Explicit Allocations" all DOM and layout measurements are segmented by window, but in "Other Measurements" those measurements are aggregated into totals for the whole browser.

	~~Sub-trees can be collapsed or expanded by clicking on them. If you find any particular tree (especially~~ "~~explicit~~"~~) overwhelming, it can be helpful to collapse all the sub~~-~~trees immediately below~~ the ~~root~~, ~~and then gradually expand~~ the ~~sub-trees of interest~~.		On Firefox OS, there is also a "System" section which contains whole-device measurements obtained from the operating system. Among other things, this section is useful for understanding exactly how the whole device's memory is being used.

	=== Notable measurements ===		=== Notable measurements ===
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	* "resident". Physical memory usage. If you want a single measurement to summarize memory usage, this is probably the best one.		* "resident". Physical memory usage. If you want a single measurement to summarize memory usage, this is probably the best one.
	* "vsize". Virtual memory usage.		* "vsize". Virtual memory usage.
	* "heap-unclassified". This is heap-allocated memory that is not measured by any memory reporter. This is ~~often~~ 10--15% of "explicit". If it gets higher, it indicates that additional memory reporters should be added. [[Performance/MemShrink/DMD]] can be used to ~~understand~~ where these memory reporters should be added.		* "heap-unclassified". This is heap-allocated memory that is not measured by any memory reporter. This is typically 10--15% of "explicit". If it gets higher, it indicates that additional memory reporters should be added. [[Performance/MemShrink/DMD]] can be used to determine where these memory reporters should be added.

Nnethercote: /* Things that make your life easier */

2014-05-26T01:07:15Z

Things that make your life easier

← Older revision		Revision as of 01:07, 26 May 2014
Line 8:		Line 8:

	You can copy and paste part or all of about:memory's contents into any text buffer. This is much easier than taking screenshots.		You can copy and paste part or all of about:memory's contents into any text buffer. This is much easier than taking screenshots.

			Memory reports are saved to file as gzipped JSON, and so have a .json.gz extension. These files can be loaded as is, but they can also be loaded after unzipping.

	== Measurements ==		== Measurements ==

Nnethercote: /* Basics */

2014-05-26T01:05:47Z

Basics

← Older revision		Revision as of 01:05, 26 May 2014
Line 24:		Line 24:
	└───0 (00.00%) ── dead		└───0 (00.00%) ── dead

	This allows measurements to be broken down into further categories, sub-categories, sub-sub-categories, etc., as needed. All the measurements within a single tree are non-overlapping.		This allows measurements to be broken down into further categories, sub-categories, sub-sub-categories, etc., as needed. The value of each internal node is the sum of all its children. All the measurements within a single tree are non-overlapping.

	Tree paths can be written using '/' as a separator. For example, "preference/referent/weak/alive" indicates a one path to a leaf node in the above tree.		Tree paths can be written using '/' as a separator. For example, "preference/referent/weak/alive" indicates a one path to a leaf node in the above tree.

Nnethercote at 03:37, 23 May 2014

2014-05-23T03:37:14Z

← Older revision		Revision as of 03:37, 23 May 2014
Line 1:		Line 1:
	~~todo~~		about:memory is a special page that lets you view, save, load, and diff detailed measurements of Firefox's memory usage. It also lets you do other memory-related operations like trigger GC and CC, dump GC & CC logs, and dump DMD reports.

			Type "about:memory" into the browser's address bar to view it.

			== Things that make your life easier ==

			Almost everything you see in about:memory has an explanatory tool-tip. Hover over any button to see a description of what it does. Hover over any measurement to see a description of what it means.

			You can copy and paste part or all of about:memory's contents into any text buffer. This is much easier than taking screenshots.

			== Measurements ==

			=== Basics ===

			Most measurements use bytes as their unit, but some are counts or percentages.

			Most measurements are presented within trees. For example:

			585 (100.0%) -- preference-service
			└──585 (100.0%) -- referent
			├──493 (84.27%) ── strong
			└───92 (15.73%) -- weak
			├──92 (15.73%) ── alive
			└───0 (00.00%) ── dead

			This allows measurements to be broken down into further categories, sub-categories, sub-sub-categories, etc., as needed. All the measurements within a single tree are non-overlapping.

			Tree paths can be written using '/' as a separator. For example, "preference/referent/weak/alive" indicates a one path to a leaf node in the above tree.

			=== Sections ===

			Memory reports are displayed on a per-process basis. Within each process's measurements, there are two sections.

			* "Explicit Allocations". This tree measures all the memory allocated via explicit calls to heap allocation functions (such as <tt>malloc</tt> and <tt>new</tt>) and to non-heap allocations functions (such as <tt>mmap</tt> and <tt>VirtualAlloc</tt>).
			* "Other Measurements". This collection of trees includes many that cross-cut the measurements in the "Explicit Allocations" tree. For example, in "Explicit Allocations" all DOM and layout measurements are segmented by window, but in "Other Measurements" those measurements are aggregated into totals for the whole browser.

			Sub-trees can be collapsed or expanded by clicking on them. If you find any particular tree (especially "explicit") overwhelming, it can be helpful to collapse all the sub-trees immediately below the root, and then gradually expand the sub-trees of interest.

			=== Notable measurements ===

			The exact set of measurements shown in about:memory changes frequently. However, here are some notable ones.

			* "explicit". This value is at the root of the tree in the "Explicit Allocations" section. As mentioned above, this represents all the memory allocated via explicit calls to allocation functions.
			* "resident". Physical memory usage. If you want a single measurement to summarize memory usage, this is probably the best one.
			* "vsize". Virtual memory usage.
			* "heap-unclassified". This is heap-allocated memory that is not measured by any memory reporter. This is often 10--15% of "explicit". If it gets higher, it indicates that additional memory reporters should be added. [[Performance/MemShrink/DMD]] can be used to understand where these memory reporters should be added.

Nnethercote: Created page with "todo"

2014-05-22T03:52:31Z

Created page with "todo"

New page

todo