Re: Reduce timing overhead of EXPLAIN ANALYZE using rdtsc?

Andrew Dunstan <andrew@dunslane.net>

From: Andrew Dunstan <andrew@dunslane.net>

To: Andres Freund <andres@anarazel.de>, Lukas Fittl <lukas@fittl.com>

Cc: pgsql-hackers <pgsql-hackers@postgresql.org>, David Geier <geidav.pg@gmail.com>

Date: 2026-04-09T09:27:36Z

Lists: pgsql-hackers

On 2026-04-08 We 11:13 AM, Andres Freund wrote:
> Hi,
>
> Andrew, what's drongo running on? I assume it's some kind of VM? What
> virtualization technology?


It's an AWS EC2 instance.

cheers

andrew

--
Andrew Dunstan
EDB:https://www.enterprisedb.com

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: Show additional TSC clock source debug info
- 5ba34f6dc838 19 (unreleased) landed
instrumentation: Avoid CPUID 0x15/0x16 for Hypervisor TSC frequency
- 7fc36c5db550 19 (unreleased) landed
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
Check for __cpuidex and __get_cpuid_count separately
- effaa464afd3 19 (unreleased) landed
pg_test_timing: Reduce per-loop overhead
- 82c0cb4e672d 19 (unreleased) landed
Refactor handling of x86 CPUID instructions
- be6a7494d2e3 19 (unreleased) landed
instrumentation: Drop INSTR_TIME_SET_CURRENT_LAZY macro
- 9d6294c09ed0 19 (unreleased) landed
Rename pg_crc32c_sse42_choose.c for general purpose
- b9278871f991 19 (unreleased) cited
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