Re: measuring swap partition speed
- Go to: [ bottom of page ] [ top of archives ] [ this month ]
Date: Sat, 23 Dec 2023 20:11:40 UTC
void <void_at_f-m.fm> wrote on Date: Sat, 23 Dec 2023 15:59:21 UTC : > On Thu, 21 Dec 2023, at 17:32, Mark Millard wrote: > > [For this message I'm replying to just the one point because I > > expect that it is rather important to your context.] > > > swapfile write requires the write request to come through the filesystem > > write path, which might require the filesystem to allocate more memory > > and read some data. E.g. it is known that any ZFS write request > > allocates memory, and that write request on large UFS file might require > > allocating and reading an indirect block buffer to find the block number > > of the written block, if the indirect block was not yet read. > > Are nfs writes the same as a "write request through the filesystem write path" ? > If not the same, then the same deleterious effect in the context? I expect that NFS would have the issue: SOMETHING(s) might require NFS to allocate more memory during the attempt to do a paging I/O of interest But I'm no NFS expert. Basically, any additional layers that create additional memory allocations in managing the paging I/O contribute to such issues. The more allocations in trying to do the paging I/O, the worse the issue. Even just the fact that umass is involved for the USB I/O contributes some risk, if I understand right. (Seems to be rather low risk of itself.) === Mark Millard marklmi at yahoo.com