Îïèñàíèå îøèáêè îò 19.12.2005. Èíòåðâàëüíûé òàéìåð íåïðàâèëüíî ðàáîòàåò íà ñèñòåìàõ ñ NPTL

Ñôîðìèðîâàëîñü ïîäîçðåíèå íà áàãó â ðàáîòå èíòåðâàëüíîãî òàéìåðà è ñèãíàëîâ â NPTL íà ÿäðàõ >= 2.6.12.
Ïðîáëåìà â ñëåäóþùåì:

• èìååòñÿ çàäà÷à â êîòîðîé ñîçäà¸òñÿ ìíîæåñòâî ïîòîêîâ;
• êàæäûé ïîòîê ñîçäà¸ò ñîáñòâåííûé èíòåðâàëüíûé òàéìåð ñ èíäèâèäóàëüíûì ïåðèîäîì ñ ïîìîùüþ ôóíêöèé: setitimer() èëè timer_create();
• îáðàáîò÷èê ñèãíàëîâ äëÿ âñåõ ýòî ôóíêöèÿ ïóñòûøêà óêàçàííàÿ ñ ïîìîùüþ: signal();
• êàæäûé ïîòîê öèêëè÷åñêè âûïîëíÿåò ñâîé êîä ñ îæèäàíèåì ñèãíàëà ïîñëå ýòîãî ñ ïîìîùüþ ôóíêöèé: sigwait() èëè pause();
• íà ñèñòåìàõ áåç NPTL è íà ñèñòåìàõ ñ NPTL íà ÿäðàõ 2.4 (ALTLinux2.4, ASPLinux9) ñèãíàëû øëþòñÿ ïîòîêàì è îíè ïåðèîäè÷åñêè âûïîëíÿþò ñâîé êîä;
• íà ñèñòåìàõ ñ NPTL è ÿäðàìè >= 2.6.12 (SuSE10_64, Mandriva2006, FedoreCore4_64) ñèãíàëû øëþòñÿ ïðîöåññó, íî íå ïîòîêàì, â ðåçóëüòàòå ÷åãî ïîòîêè ñòîÿò íà îæèäàíèè ñèãíàëà;

Äëÿ ïðèìåðà íàïèñàíà òåñòîâàÿ ïðîãðàììà êîòîðàÿ âîñïðîèçâîäèò ýòó ïðîáëåìó. Íà ñèñòåìàõ áåç NPTL è íà ñèñòåìàõ ñ NPTL íà ÿäðàõ 2.4 (ALTLinux2.4, ASPLinux9) ðåçóëüòàòû å¸ ðàáîòû òàêèå:

ALTLinux2.4

roman@roman my]$ ./a.out Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test. Pthread inteval timer test.

Íà ñèñòåìàõ ñ NPTL è ÿäðàìè >= 2.6.12 (SuSE10_64, Mandriva2006, FedoreCore4_64) ðåçóëüòàòû å¸ ðàáîòû òàêèå:

SuSE 10 (64)

roman@roman:~/Documents> ./a.out Pthread inteval timer test. Signal test: 10. Exit from programm! Signal test: 10. Exit from programm! Signal test: 10. Exit from programm! Signal test: 10. Exit from programm! Signal test: 10. Exit from programm! Signal test: 10. Exit from programm! Signal test: 10. Exit from programm! Signal test: 10. Exit from programm! Signal test: 10. Exit from programm! Signal test: 10. Exit from programm! Signal test: 10. Exit from programm! Signal test: 10.

Èç ïðîòîêîëà âûïîëíåíèÿ ïðîãðàììû íà SuSE10 âèäíî ÷òî:

• öèêë ïîòîêà îäèí ðàç âûïîëíÿåòñÿ è ñòîïîðèòñÿ íà îæèäàíèè ñèãíàëà ôóíêöèåé sigwait(