Re: Reduce timing overhead of EXPLAIN ANALYZE using rdtsc?

David Geier <geidav.pg@gmail.com>

From: David Geier <geidav.pg@gmail.com>

To: Andres Freund <andres@anarazel.de>

Cc: Pavel Stehule <pavel.stehule@gmail.com>, Tomas Vondra <tomas.vondra@enterprisedb.com>, vignesh C <vignesh21@gmail.com>, Lukas Fittl <lukas@fittl.com>, Michael Paquier <michael@paquier.xyz>, Ibrar Ahmed <ibrar.ahmad@gmail.com>, Maciek Sakrejda <m.sakrejda@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2023-02-20T10:36:32Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

pg_test_timing: Also test RDTSC[P] timing, report time source, TSC frequency
- 16fca4825483 19 (unreleased) landed
Allow retrieving x86 TSC frequency/flags from CPUID
- bcb2cf41f964 19 (unreleased) landed
instrumentation: Standardize ticks to nanosecond conversion method
- 0022622c93d9 19 (unreleased) landed
instrumentation: Use Time-Stamp Counter on x86-64 to lower overhead
- 294520c44487 19 (unreleased) landed
Zero initialize uses of instr_time about to trigger compiler warnings
- 25b2aba0c3a5 16.0 landed
instr_time: Represent time as an int64 on all platforms
- 03023a2664f8 16.0 landed
Add 250c8ee07ed to git-blame-ignore-revs
- ff23b592ad66 16.0 cited

Attachments

v9-0001-instr_time-Add-INSTR_TIME_SET_SECONDS-INSTR_TIME_.patch (text/x-patch) patch v9-0001
v9-0002-wip-report-nanoseconds-in-pg_test_timing.patch (text/x-patch) patch v9-0002
v9-0003-Use-time-stamp-counter-to-measure-time-on-Linux-x.patch (text/x-patch) patch v9-0003

Hi!

On 2/14/23 13:48, David Geier wrote:
>
> It still fails.
>
> I'll get Cirrus-CI working on my own Github fork so I can make sure it 
> really compiles on all platforms before I submit a new version.

It took some time until Cirrus CI allowed me to run tests against my new 
GitHub account (there's a 3 days freeze to avoid people from getting 
Cirrus CI nodes to mine bitcoins :-D). Attached now the latest patch 
which passes builds, rebased on latest master.

I also reviewed the first two patches a while ago in [1]. I hope we can 
progress with them to further reduce the size of this patch set.

Beyond that: I could work on support for more OSs (e.g. starting with 
Windows). Is there appetite for that or do we rather want to instead 
start with a smaller patch?

[1] 
https://www.postgresql.org/message-id/3ac157f7-085d-e071-45fc-b87cd306360c%40gmail.com

-- 
David Geier
(ServiceNow)