Action required: Rawhide: /tmp is now on tmpfs

Reindl Harald h.reindl at thelounge.net
Sat Jun 2 17:38:17 UTC 2012


Am 02.06.2012 19:24, schrieb Gregory Maxwell:
> Tmpfs just has the advantage of minimizing the disk activity— both in
> cases where none is needed, and in cases where it is.

you refuse to understand if some app creates a 2 GB
file in /tmp and does not remove your only pressure
is to the page-cache which is not the same as start
swapping because memory pressure

> Really, you should try it. It works very well and does not
> make your machine perform poorly, even when under memory
> pressure

it have used tmpfs probably long before you even knew it
exists (on some workloads even for /tmp) but it is not
the holy grail for each workload and so a wrong DEFAULT

Am 02.06.2012 19:25, schrieb Chris Adams:
> Once upon a time, Reindl Harald <h.reindl at thelounge.net> said:
>> Am 02.06.2012 04:08, schrieb Jesse Keating:
>>> The useless 2G file will get swapped out, not important things that are actively being used in ram
>>
>> it does not matter WHAT get swapped out
>> from the moment on the system starts to swap performance sucks
> 
> With /tmp-on-storage, that 2G file would have already caused a large
> amount of I/O; it is the same 2G being written on to the same storage,
> whether a /tmp filesystem or swap

you refuse to understand the difference WHEN this happens
writing 2 GB to disk on modern fileystems is meaningless

having the 2 GB in memory and a by the introduced memory
pressure swapped out application get the focus and allocate
a large amount of memory while loading large data you have MULTIPLE
pressure

* relaod the application form swap
* load application data from disk
* write /tmp and/or other data to disk

so you have THREE heavy disk usage patterns with
mixed read and write - have fun with your coffee

again: there may be workloads where it is nice and a small
improvement as i have some of them by my self but that does
NOT qulify it as a os-wide default





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