Hi, >From: Chas. Owens [mailto:chas.ow...@gmail.com] >Sent: Monday, April 04, 2011 6:40 AM
>My bet is you don't have enough RAM to hold all of that data; your OS >is being forced to use swap. Your poor machine is so swamped it is >taking that long to get back to normal. >Each key in your hash is probably taking up around fifteen bytes and >each value is probably around four bytes (if not eight). You have >165,000,006 entries. That means you need around 3 gigabytes of RAM >for the data alone. That doesn't count the hash that holds the data, >perl itself, or any other programs you may be running. You have a good point. I could not think of anything else, and suspected it might be the cause. But: The servers that I have tested have light load and have large memory (at least 10 times more than the process that I ran would need). I choose those numbers to simulate memory use similar to my real process. Since "top" command on Linux almost always shows "used" value that nearly match the "total" and Linux like to use any spare memory to cache disk blocks, I can hardly tell. "free -m " did show that less than half of the total memory is used. So I don't believe the server is swamped. Thanks -----Original Message----- From: Chas. Owens [mailto:chas.ow...@gmail.com] Sent: Monday, April 04, 2011 6:40 AM To: TAO, NENGBING [AG/1005] Cc: beginners-digest-h...@perl.org; beginners@perl.org Subject: Re: Excessive wait time after fork On Sat, Apr 2, 2011 at 12:06, TAO, NENGBING [AG/1005] <nengbing....@monsanto.com> wrote: > Hi, > > I noticed that after fork, the wait time is excessive (my other > test waited for hours). Is this a known problem, how to get around it? snip > child 3 AFTER sub call :Sat Apr 2 10:45:01 2011 numKeys:4000001 > child 4 BEFORE sub call : Sat Apr 2 10:44:54 2011 > child 4 AFTER sub call :Sat Apr 2 10:45:04 2011 numKeys:5000001 > child 5 BEFORE sub call : Sat Apr 2 10:44:54 2011 > child 5 AFTER sub call :Sat Apr 2 10:45:06 2011 numKeys:6000001 > child 1 BEFORE sub call : Sat Apr 2 10:44:54 2011 > child 1 AFTER sub call :Sat Apr 2 10:45:41 2011 numKeys:20000001 > child 2 BEFORE sub call : Sat Apr 2 10:44:54 2011 > child 2 AFTER sub call :Sat Apr 2 10:45:56 2011 numKeys:30000001 > child 0 BEFORE sub call : Sat Apr 2 10:44:54 2011 > child 0 AFTER sub call :Sat Apr 2 10:48:45 2011 numKeys:100000001 # snip My bet is you don't have enough RAM to hold all of that data; your OS is being forced to use swap. Your poor machine is so swamped it is taking that long to get back to normal. Each key in your hash is probably taking up around fifteen bytes and each value is probably around four bytes (if not eight). You have 165,000,006 entries. That means you need around 3 gigabytes of RAM for the data alone. That doesn't count the hash that holds the data, perl itself, or any other programs you may be running. -- Chas. Owens wonkden.net The most important skill a programmer can have is the ability to read. This e-mail message may contain privileged and/or confidential information, and is intended to be received only by persons entitled to receive such information. If you have received this e-mail in error, please notify the sender immediately. Please delete it and all attachments from any servers, hard drives or any other media. Other use of this e-mail by you is strictly prohibited. All e-mails and attachments sent and received are subject to monitoring, reading and archival by Monsanto, including its subsidiaries. The recipient of this e-mail is solely responsible for checking for the presence of "Viruses" or other "Malware". Monsanto, along with its subsidiaries, accepts no liability for any damage caused by any such code transmitted by or accompanying this e-mail or any attachment. The information contained in this email may be subject to the export control laws and regulations of the United States, potentially including but not limited to the Export Administration Regulations (EAR) and sanctions regulations issued by the U.S. Department of Treasury, Office of Foreign Asset Controls (OFAC). As a recipient of this information you are obligated to comply with all applicable U.S. export laws and regulations.
