JDK10 RFR: 8165437 Evaluate the use of gettimeofday in Networking code

[Langer, Christoph]

Hi Vyom,

I’ve just got a small formatting remark about the order of includes:

Generally I tried to follow the rule 1. Common os headers, 2. Platform os headers,  3. Jvm/jdk headers, 4. JNI headers in my latest refactorings. So, to keep this up, can you move #include “jvm.h” in the line before #include “net_util.h” in each file? And pull it before the JNI headers. Like, e.g. in net_util_md.c you should move #include "jvm.h" to line 52.

Thanks & Best regards
Christoph

From: net-dev [mailto:net-dev-bounces at openjdk.java.net] On Behalf Of Vyom Tewari
Sent: Donnerstag, 27. April 2017 06:16
To: Thomas Stüfe <thomas.stuefe at gmail.com>; Chris Hegarty <chris.hegarty at oracle.com>
Cc: net-dev <net-dev at openjdk.java.net>
Subject: Re: JDK10 RFR: 8165437 Evaluate the use of gettimeofday in Networking code


Hi,

please find the updated webrev(http://cr.openjdk.java.net/~vtewari/8165437/webrev0.7/index.html).

Thanks,

Vyom



On Tuesday 25 April 2017 07:34 PM, Thomas Stüfe wrote:
Hi Chris, Vyom,

I have preferences as expressed earlier, but no strong emotions. I can live with the fix as it is now.

Thanks all, and Kind Regards, Thomas


On Tue, Apr 25, 2017 at 3:31 PM, Chris Hegarty <chris.hegarty at oracle.com<mailto:chris.hegarty at oracle.com>> wrote:
> On Tue, Apr 18, 2017 at 7:08 AM, Vyom Tewari <vyom.tewari at oracle.com<mailto:vyom.tewari at oracle.com>> wrote:
> ...
>
> Thanks for review, please find the updated webrev(http://cr.openjdk.java.net/~vtewari/8165437/webrev0.6/index.html<http://cr.openjdk.java.net/%7Evtewari/8165437/webrev0.6/index.html>)

The changes mainly look good to me, just a few comments:

1) src/java.base/unix/native/libnet/PlainSocketImpl.c

   L235     jlong nanoTimeout = timeout * NET_NSEC_PER_MSEC;

   Can you please move this to the latest block of code that requires it, i.e..
   just after L327 if (connect_rv != 0) { …

2) src/java.base/share/native/libnet/net_util.h

   Should these definitions be moved to src/java.base/unix/native/libnet/net_util_md.h?


Regarding JVM_NanoTime being a JVM_LEAF and/or taking a JNIEnv (
both of which are, in todays hotspot VM, effectively ignored ), this is a
separate issue. I have raised it off list with others from the VM team,
without much interest. I will refrain from filing a JIRA issue to track potential
changes in the VM for this. Others are welcome to do so, if they wish. I
suggest that we simply continue to pass a valid JNIEnv, since it is not
much extra effort to do so. ( this can be refactored later, if the VM interface
is ever updated ).


> On 24 Apr 2017, at 12:07, Thomas Stüfe <thomas.stuefe at gmail.com<mailto:thomas.stuefe at gmail.com>> wrote:
>
> ...
> That aside, I am not a big fan of the removal of the old NET_Timeout. Before, there were two functions, "NET_Timeout" just taking the timeout value, "NET_Timeout0" taking a timeout and a start value. You removed the first variant and therefore added the many additional JVM_NanoTime() calls at NET_Timeout callsites. This makes the code harder to read and also kind of exposes the internal implementation of NET_Timeout (namely the fact that NET_Timeout uses JVM_NanoTime for time measurement). Could you please let both variants live, optionally with better names?

I think that it may not be worth added back the simpler variant. It
would only be used by PlainDatagramSocketImpl, correct? All other
usages would use the variant that accepts the current nano time.

-Chris.


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/net-dev/attachments/20170427/56025759/attachment-0001.html>