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From: Steven Rostedt <rostedt@goodmis.org>
To: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
Cc: linux-trace-devel@vger.kernel.org
Subject: Re: [PATCH v6 25/45] trace-cmd: Read compressed trace data
Date: Mon, 21 Jun 2021 19:23:10 -0400	[thread overview]
Message-ID: <20210621192310.43e68a92@gandalf.local.home> (raw)
In-Reply-To: <20210614075029.598048-26-tz.stoyanov@gmail.com>

On Mon, 14 Jun 2021 10:50:09 +0300
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> When reading a trace.dat file of version 7, uncompress the trace data.
> The trace data for each CPU is uncompressed in a temporary file, located
> in /tmp directory with prefix "trace_cpu_data".

With large trace files, this will be an issue. Several systems setup the
/tmp directory as a ramfs file system (that is, it is locate in ram, and
not backed up on disk). If you have very large trace files, which you would
if you are going to bother compressing them, by uncompressing them into
/tmp, it could take up all the memory of the machine, or easily fill the
/tmp limit.

Simply uncompressing the entire trace data is not an option. The best we
can do is to uncompress on a as needed basis. That would require having
meta data that is stored to know what pages are compressed.

-- Steve

  reply	other threads:[~2021-06-21 23:23 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-14  7:49 [PATCH v6 00/45] Add trace file compression Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 01/45] trace-cmd library: Remove unused private APIs for creating trace files Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 02/45] trace-cmd library: Remove unused API tracecmd_update_option Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 03/45] trace-cmd: Check if file version is supported Tzvetomir Stoyanov (VMware)
2021-06-21 22:27   ` Steven Rostedt
2021-06-21 22:36     ` Steven Rostedt
2021-06-14  7:49 ` [PATCH v6 04/45] trace-cmd library: Add new API to get file version of input handler Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 05/45] trace-cmd library: Select the file version when writing trace file Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 06/45] trace-cmd: Add APIs for library initialization and free Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 07/45] trace-cmd library: Add support for compression algorithms Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 08/45] trace-cmd list: Show supported " Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 09/45] trace-cmd library: Bump the trace file version to 7 Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 10/45] trace-cmd library: Compress part of the trace file Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 11/45] trace-cmd library: Read compressed " Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 12/45] trace-cmd library: Add new API to get compression of input handler Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 13/45] trace-cmd library: Inherit compression algorithm from input file Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 14/45] trace-cmd library: Extend the create file APIs to support different compression Tzvetomir Stoyanov (VMware)
2021-06-14  7:49 ` [PATCH v6 15/45] trace-cmd record: Add new parameter --compression Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 16/45] trace-cmd dump: Add support for trace files version 7 Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 17/45] trace-cmd library: Add support for zlib compression library Tzvetomir Stoyanov (VMware)
2021-06-22  1:26   ` Steven Rostedt
2021-06-22 10:29     ` Tzvetomir Stoyanov
2021-06-22 13:31       ` Steven Rostedt
2021-06-14  7:50 ` [PATCH v6 18/45] trace-cmd library: Hide the logic for updating buffer offset Tzvetomir Stoyanov (VMware)
2021-06-22  2:10   ` Steven Rostedt
2021-06-14  7:50 ` [PATCH v6 19/45] trace-cmd: Move buffers description outside of options Tzvetomir Stoyanov (VMware)
2021-06-21 23:07   ` Steven Rostedt
2021-06-14  7:50 ` [PATCH v6 20/45] trace-cmd library: Track the offset in the option section in the trace file Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 21/45] trace-cmd library: Add compression of the option section of " Tzvetomir Stoyanov (VMware)
2021-06-21 23:10   ` Steven Rostedt
2021-06-22 10:43     ` Tzvetomir Stoyanov
2021-06-14  7:50 ` [PATCH v6 22/45] trace-cmd library: Refactor the logic for writing trace data in the file Tzvetomir Stoyanov (VMware)
2021-06-21 23:12   ` Steven Rostedt
2021-06-14  7:50 ` [PATCH v6 23/45] trace-cmd library: Add APIs for read and write compressed data in chunks Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 24/45] trace-cmd: Compress trace data Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 25/45] trace-cmd: Read compressed " Tzvetomir Stoyanov (VMware)
2021-06-21 23:23   ` Steven Rostedt [this message]
2021-06-22 10:50     ` Tzvetomir Stoyanov
2021-06-22 13:51       ` Steven Rostedt
2021-06-14  7:50 ` [PATCH v6 26/45] trace-cmd library: Compress latency " Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 27/45] trace-cmd: Read compressed " Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 28/45] trace-cmd library: Reuse within the library the function that checks file state Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 29/45] trace-cmd library: Make tracecmd_copy_headers() to work with output handler Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 30/45] trace-cmd: Do not use trace file compression with streams Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 31/45] trace-cmd library: Add new API to get file version of output handler Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 32/45] trace-cmd: Add file state parameter to tracecmd_copy Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 33/45] trace-cmd: Copy CPU count in tracecmd_copy Tzvetomir Stoyanov (VMware)
2021-06-21 23:27   ` Steven Rostedt
2021-06-14  7:50 ` [PATCH v6 34/45] trace-cmd: Copy buffers description " Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 35/45] trace-cmd: Copy options " Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 36/45] trace-cmd library: Refactor the logic for writing CPU trace data Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 37/45] trace-cmd library: Refactor the logic for writing CPU instance " Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 38/45] trace-cmd: Copy trace data in tracecmd_copy Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 39/45] trace-cmd: Add compression parameter to tracecmd_copy Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 40/45] trace-cmd: Add new command "trace-cmd convert" Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 41/45] trace-cmd record: Update man page Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 42/45] trace-cmd: Add convert " Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 43/45] trace-cmd: Update bash completion Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 44/45] trace-cmd list: Update the man page Tzvetomir Stoyanov (VMware)
2021-06-14  7:50 ` [PATCH v6 45/45] trace-cmd: Update trace.dat " Tzvetomir Stoyanov (VMware)
2021-06-22  0:37   ` Steven Rostedt
2021-06-22 11:05     ` Tzvetomir Stoyanov
2021-06-22 13:58       ` Steven Rostedt
2021-06-22  2:22 ` [PATCH v6 00/45] Add trace file compression Steven Rostedt

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