Messages in this thread | | | From | Pavel Tatashin <> | Date | Wed, 6 Dec 2017 13:11:14 -0500 | Subject | Re: [PATCH v9 0/6] Early boot time stamps for x86 |
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Hi Thomas and Peter,
I have a few minor changes to this patch series Such as include: Reviewed-by: Dou Liyang <douly.fnst@cn.fujitsu.com> And a couple minor cosmetic/description changes, but I would like to get your comments first before sending out an updated series.
Thank you, Pavel
On Wed, Nov 15, 2017 at 9:32 PM, Pavel Tatashin <pasha.tatashin@oracle.com> wrote: > changelog > --------- > v9 - v8 > - Addressed more comments from Dou Liyang > > v8 - v7 > - Addressed comments from Dou Liyang: > - Moved tsc_early_init() and tsc_early_fini() to be all inside > tsc.c, and changed them to be static. > - Removed warning when notsc parameter is used. > - Merged with: > https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git > > v7 - v6 > - Removed tsc_disabled flag, now notsc is equivalent of > tsc=unstable > - Simplified changes to sched/clock.c, by removing the > sched_clock_early() and friends as requested by Peter Zijlstra. > We know always use sched_clock() > - Modified x86 sched_clock() to return either early boot time or > regular. > - Added another example why ealry boot time is important > > v5 - v6 > - Added a new patch: > time: sync read_boot_clock64() with persistent clock > Which fixes missing __init macro, and enabled time discrepancy > fix that was noted by Thomas Gleixner > - Split "x86/time: read_boot_clock64() implementation" into a > separate patch > > v4 - v5 > - Fix compiler warnings on systems with stable clocks. > > v3 - v4 > - Fixed tsc_early_fini() call to be in the 2nd patch as reported > by Dou Liyang > - Improved comment before __use_sched_clock_early to explain why > we need both booleans. > - Simplified valid_clock logic in read_boot_clock64(). > > v2 - v3 > - Addressed comment from Thomas Gleixner > - Timestamps are available a little later in boot but still much > earlier than in mainline. This significantly simplified this > work. > > v1 - v2 > In patch "x86/tsc: tsc early": > - added tsc_adjusted_early() > - fixed 32-bit compile error use do_div() > > Adding early boot time stamps support for x86 machines. > SPARC patches for early boot time stamps are already integrated into > mainline linux. > > Sample output > ------------- > Before: > https://hastebin.com/jadaqukubu.scala > > After: > https://hastebin.com/nubipozacu.scala > > For more exaples how early time stamps are used, see this work: > > Example 1: > https://lwn.net/Articles/734374/ > - Without early boot time stamps we would not know about the extra time > that is spent zeroing struct pages early in boot even when deferred > page initialization. > > Example 2: > https://patchwork.kernel.org/patch/10021247/ > - If early boot timestamps were available, the engineer who introduced > this bug would have noticed the extra time that is spent early in boot. > > Pavel Tatashin (6): > x86/tsc: remove tsc_disabled flag > time: sync read_boot_clock64() with persistent clock > x86/time: read_boot_clock64() implementation > sched: early boot clock > x86/paravirt: add active_sched_clock to pv_time_ops > x86/tsc: use tsc early > > arch/arm/kernel/time.c | 2 +- > arch/s390/kernel/time.c | 2 +- > arch/x86/include/asm/paravirt.h | 2 +- > arch/x86/include/asm/paravirt_types.h | 1 + > arch/x86/kernel/paravirt.c | 1 + > arch/x86/kernel/time.c | 30 +++++++++ > arch/x86/kernel/tsc.c | 117 ++++++++++++++++++++++++++++------ > arch/x86/xen/time.c | 7 +- > include/linux/timekeeping.h | 3 +- > kernel/sched/clock.c | 10 ++- > kernel/time/timekeeping.c | 8 ++- > 11 files changed, 153 insertions(+), 30 deletions(-) > > -- > 2.15.0 >
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