* xxhash ? @ 2017-12-28 6:13 Joakim Tjernlund 2017-12-28 9:38 ` Richard Weinberger 0 siblings, 1 reply; 5+ messages in thread From: Joakim Tjernlund @ 2017-12-28 6:13 UTC (permalink / raw) To: linux-mtd@lists.infradead.org Now that xxhash is in the tree one could look at replacing crc32 in JFFS2/UBI. This would make checksumming much faster. Just an idea Jocke ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: xxhash ? 2017-12-28 6:13 xxhash ? Joakim Tjernlund @ 2017-12-28 9:38 ` Richard Weinberger 2017-12-28 9:44 ` Joakim Tjernlund 0 siblings, 1 reply; 5+ messages in thread From: Richard Weinberger @ 2017-12-28 9:38 UTC (permalink / raw) To: Joakim Tjernlund; +Cc: linux-mtd@lists.infradead.org Joakim, On Thu, Dec 28, 2017 at 7:13 AM, Joakim Tjernlund <Joakim.Tjernlund@infinera.com> wrote: > Now that xxhash is in the tree one could look at replacing > crc32 in JFFS2/UBI. This would make checksumming much faster. Since this will require a change of the on-disk format we have to be very careful. Do you have a use-case where crc32 is the bottle neck? -- Thanks, //richard ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: xxhash ? 2017-12-28 9:38 ` Richard Weinberger @ 2017-12-28 9:44 ` Joakim Tjernlund 2017-12-28 10:06 ` Richard Weinberger 0 siblings, 1 reply; 5+ messages in thread From: Joakim Tjernlund @ 2017-12-28 9:44 UTC (permalink / raw) To: richard.weinberger@gmail.com; +Cc: linux-mtd@lists.infradead.org On Thu, 2017-12-28 at 10:38 +0100, Richard Weinberger wrote: > CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe. > > > Joakim, > > On Thu, Dec 28, 2017 at 7:13 AM, Joakim Tjernlund > <Joakim.Tjernlund@infinera.com> wrote: > > Now that xxhash is in the tree one could look at replacing > > crc32 in JFFS2/UBI. This would make checksumming much faster. > > Since this will require a change of the on-disk format we have to be > very careful. > Do you have a use-case where crc32 is the bottle neck? Not directly, I remember the good old days when mounting took forever, mostly due to crc32. I then optimized crc32(the big tables you have today) and some other JFFS2 optimizations. Since crc32 is used everywhere in JFFS2 I figure xxhash would help, especially on low end CPUs Jocke ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: xxhash ? 2017-12-28 9:44 ` Joakim Tjernlund @ 2017-12-28 10:06 ` Richard Weinberger 2017-12-28 10:52 ` Joakim Tjernlund 0 siblings, 1 reply; 5+ messages in thread From: Richard Weinberger @ 2017-12-28 10:06 UTC (permalink / raw) To: Joakim Tjernlund, linux-mtd@lists.infradead.org Am Donnerstag, 28. Dezember 2017, 10:44:05 CET schrieb Joakim Tjernlund: > On Thu, 2017-12-28 at 10:38 +0100, Richard Weinberger wrote: > > > CAUTION: This email originated from outside of the organization. Do not > > click links or open attachments unless you recognize the sender and know > > the content is safe. > > > > Joakim, > > > > On Thu, Dec 28, 2017 at 7:13 AM, Joakim Tjernlund > > <Joakim.Tjernlund@infinera.com> wrote: > > > > > Now that xxhash is in the tree one could look at replacing > > > crc32 in JFFS2/UBI. This would make checksumming much faster. > > > > > > Since this will require a change of the on-disk format we have to be > > very careful. > > Do you have a use-case where crc32 is the bottle neck? > > > Not directly, I remember the good old days when mounting took forever, > mostly due to crc32. I then optimized crc32(the big tables you have today) > and some other JFFS2 optimizations. Since crc32 is used everywhere in JFFS2 > I figure xxhash would help, especially on low end CPUs Unless this gives a decent speedup I don't think we should add new features to JFFS2. For UBI/UBIFS it is a different story. Did you also tests with UBI? Thanks, //richard ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: xxhash ? 2017-12-28 10:06 ` Richard Weinberger @ 2017-12-28 10:52 ` Joakim Tjernlund 0 siblings, 0 replies; 5+ messages in thread From: Joakim Tjernlund @ 2017-12-28 10:52 UTC (permalink / raw) To: richard@nod.at, linux-mtd@lists.infradead.org On Thu, 2017-12-28 at 11:06 +0100, Richard Weinberger wrote: > CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe. > > > Am Donnerstag, 28. Dezember 2017, 10:44:05 CET schrieb Joakim Tjernlund: > > On Thu, 2017-12-28 at 10:38 +0100, Richard Weinberger wrote: > > > > > CAUTION: This email originated from outside of the organization. Do not > > > click links or open attachments unless you recognize the sender and know > > > the content is safe. > > > > > > Joakim, > > > > > > On Thu, Dec 28, 2017 at 7:13 AM, Joakim Tjernlund > > > <Joakim.Tjernlund@infinera.com> wrote: > > > > > > > Now that xxhash is in the tree one could look at replacing > > > > crc32 in JFFS2/UBI. This would make checksumming much faster. > > > > > > > > > Since this will require a change of the on-disk format we have to be > > > very careful. > > > Do you have a use-case where crc32 is the bottle neck? > > > > > > Not directly, I remember the good old days when mounting took forever, > > mostly > > due to crc32. I then optimized crc32(the big tables you have today) > > and some other JFFS2 optimizations. Since crc32 is used everywhere in JFFS2 > > I figure xxhash would help, especially on low end CPUs > > Unless this gives a decent speedup I don't think we should add new features to > JFFS2. xxhash could be worth it but someone will have to test it first > For UBI/UBIFS it is a different story. Did you also tests with UBI? Na, this was long before UBI existed :) ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2017-12-28 10:52 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2017-12-28 6:13 xxhash ? Joakim Tjernlund 2017-12-28 9:38 ` Richard Weinberger 2017-12-28 9:44 ` Joakim Tjernlund 2017-12-28 10:06 ` Richard Weinberger 2017-12-28 10:52 ` Joakim Tjernlund
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox