want faster clock_gettime
There is a large body of software today which calls clock_gettime() with extremely high frequency. On many operating systems, this functionality is implemented in such a way that it's performed entirely in userspace (via the vDSO on Linux), cutting down on the cost. This is not the case for illumos, which relies on the normal syscall path. On modern x86 hardware, clock_gettime() takes 30-50ns on Linux whereas on illumos, it's closer to 250ns+.
In order for software which heavily relies on frequent clock access, it would be nice to have access to the time via a userspace-only mechanism.
This has been implemented in SmartOS as OS-5192.
Various fixes and updates have been made to it in subsequent tickets.
Updated by Patrick Mooney about 4 years ago
The to-be-upstreamed wad will be comprised of changes from the following SmartOS tickets:
OS-5192 need faster clock_gettime OS-5515 segumap_fault can race for loaded mapping OS-5572 seg_umap should load mapping for F_SOFTLOCK OS-5637 lxbrand vdso busts golang stack budget OS-5451 comm page should not break i86xpv OS-5601 comm page symbols need ctf augmentation
Updated by Electric Monk about 4 years ago
- Status changed from New to Closed
- % Done changed from 0 to 100
commit 2428aad8462660fad2b105777063fea6f4192308 Author: Patrick Mooney <firstname.lastname@example.org> Date: 2017-02-27T19:49:06.000Z 7805 want faster clock_gettime Reviewed by: Jerry Jelinek <email@example.com> Reviewed by: Robert Mustacchi <firstname.lastname@example.org> Reviewed by: Joshua M. Clulow <email@example.com> Reviewed by: Ryan Zezeski <firstname.lastname@example.org> Reviewed by: Dan McDonald <email@example.com> Approved by: Garrett D'Amore <firstname.lastname@example.org>
Updated by Electric Monk almost 4 years ago
commit aa3c82a1eb83308d262b03dbffe9969658c7045b Author: Yuri Pankov <email@example.com> Date: 2017-03-06T15:13:07.000Z 7805 want faster clock_gettime (fix clean)