topic PHREG is slow and not using available RAM and CPU in New SAS User

PHREG is slow and not using available RAM and CPU

jamilahmed — Wed, 24 Aug 2022 23:39:40 GMT

Hi All,

One of our SAS users is using proc PHREG on a VM that has 4 vCPUs and 128GB RAM with the following config but code is running slow and only 7 GB RAM is in use out of 128. Ay Hypervisor level the consumed memory is almost 100%. Can it be because of the MEMMAXSZ value? Or something else?

-REALMEMSIZE 100G
-MEMSIZE 102G
-MAXMEMQUERY MAX
-BUFSIZE 16M
-BUFNO 16
-MEMMAXSZ 100G
-SORTSIZE 100G
-SUMSIZE 100G

Re: PHREG is slow and not using available RAM and CPU

JosvanderVelden — Thu, 25 Aug 2022 09:28:03 GMT

Have you seen this page
https://communities.sas.com/t5/SAS-Communities-Library/A-method-to-speed-up-PROC-PHREG-when-doing-a-Cox-regression/ta-p/223571 and the thread https://communities.sas.com/t5/Statistical-Procedures/my-phreg-takes-forever-to-run/td-p/236496?

Re: PHREG is slow and not using available RAM and CPU

jamilahmed — Thu, 25 Aug 2022 23:16:03 GMT

Thanks @JosvanderVelden

I will suggest these pages to the SAS users.

Re: PHREG is slow and not using available RAM and CPU

SASKiwi — Fri, 26 Aug 2022 01:13:55 GMT

Check CPU usage while the program is running. Is it using close to 100% or not? If it is close to 100% then the program is CPU bound and memory usage is not the issue. How large is the dataset being analysed (number of rows and columns)? IO can be an issue for large datasets.

Also check the CPU time versus real time figures reported for PHREG in the SAS log. Again if CPU time is similar to the real time then PHREG has a CPU bottleneck. If real time is much greater than CPU time then that suggests IO is the bottleneck.