On 31/03/2020 4:08 am, Henry Jen wrote:
Based on my understanding to gethrtime(), the main benefit is not to be
affected by settimeofday or adjtime. I think it is probably better to use
clock_gettime(CLOCK_MONOTONIC_RAW, ts);
which I checked seems to be available on both Linux and Mac. Haven’t test it
though.
Not guaranteed to be available - either clock_gettime function or that
particular clock - at build time or runtime. We use a check in the build
system to determine build-time availability for hotspot, and then use
dl_lookup etc at runtime to determine if actually available. We should
be able to get rid of this one day but we checked fairly recently and
there were still some issues.
gettimeofday is a lot better than returning 1. Otherwise call into the
VM and use JVM_NanoTime.
Cheers,
David
-----
Cheers,
Henry
On Mar 30, 2020, at 1:37 AM, Alan Bateman <alan.bate...@oracle.com> wrote:
On 30/03/2020 03:41, linzang(臧琳) wrote:
Dear All,
May I ask your help to reivew this tiny patch? Thanks.
BRs,
Lin
From: "linzang(臧琳)" <linz...@tencent.com>
Date: Thursday, March 26, 2020 at 3:13 PM
To: "core-libs-dev@openjdk.java.net" <core-libs-dev@openjdk.java.net>
Subject: RFR(S): 8241638: launcher time metrics alway report 1 on Linux when
_JAVA_LAUNCHER_DEBUG set
Dear All,
May I ask your help to review this tiny fix?
Bug: https://bugs.openjdk.java.net/browse/JDK-8241638
Webrev: http://cr.openjdk.java.net/~lzang/8241638/webrev01/
Thanks!
Using gettimeofday on non-Solaris platforms seems reasonable here. The comment
in the patch suggests Linux but it's other Unix builds too. Also just a minor
nit that the code in java.base uses 4-space indent, not 2. Looking at the patch
makes me wondering if we should remove HAVE_GETHRTIME as it seems to be only
used on Solaris and the launcher is already using #ifdef __solaris__ in several
places. Henry, do you have any comments on this?
-Alan
