Re: [fuse-devel] buffer size for writing and reading

[Nikolaus R. <Nik...@ra...>]

On Feb 12 2017, Yue Li <yli-wUU9E3n5/m56...@pu...> wrote:
> I noticed that in my testing, the writing size has always been set to 
> 131072 bytes during each write (unless the actual data size is smaller 
> than that), and during the reading, some times it is 131072, but 
> sometimes it can be changed to 65536 and other sizes.
>
> I'm wondering are these write and read sizes controlled by user 
> application (in my test i used dd), or it can actually be controlled by 
> FUSE?

Depends. read() size is controlled by the kernel, unless you use
direct_io. write() size is controlled by userspace, unless you use
writeback_cache. Your filesystem can limit the maximum size of requests
that the kernel will send.


Best,
-Nikolaus

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